Description of Nest Burrows and Burrow Colonies with Assessment of Shoreline Conditions

ANSRP Bulletin, Vol-09-1 April 2009 NNoonn--NNaattiivvee SSuucckkeerrmmoouutthh AArrmmoorreedd CCaattffiisshheess iinn FFlloorriiddaa:: DDeessccrriippttiioonn ooff NNeesstt BBuurrrroowwss aanndd BBuurrrrooww CCoolloonniieess wwiitthh AAsssseessssmmeenntt ooff SShhoorreelliinnee CCoonnddiittiioonnss by Leo G. Nico, Howard L. Jelks, and Travis Tuten

burrows in shoreline slopes for use reaches of some waterways (e.g., Purpose as spawning and nesting sites Florida’s St. Johns River) burrows (Figure 2). The burrows are re- created by Pterygoplichthys num- Non-native populations of the portedly excavated and maintained ber in the hundreds or even thou- Neotropical family Loricariidae, by adult males. In places where sands. The burrows are thought to the suckermouth armored cat- these catfish are abundant and the cause or exacerbate bank erosion. fishes, have been introduced and shore habitat suitable, burrows are Presumably, greater burrow densi- become established in many common. Burrows typically occur ties increase the likelihood of bank warm-climate regions of the in aggregates with individual colo- failure. However, there are no world, including parts of the nies consisting of a few to perhaps quantitative data available to United States (e.g., Florida and dozens of burrows. In larger adequately evaluate possible Texas). In Florida, the most common loricariid catfishes are members of the genus Pterygoplichthys (Figure 1). Over the past 20 years these catfishes have invaded most inland drainages in the central and southern parts of the Florida peninsula. In certain rivers, canals, and lakes, they are widespread and abundant, accounting for a large proportion of the total fish biomass. Adult Pterygoplichthys at- tain sizes well over 40 cm long. In both their native and intro- Figure 1. Adult male Pterygoplichthys taken from Oklawaha River drainage, duced ranges, Pterygoplichthys Florida on 4 June 2006. Fish measured 536 mm total length (415 mm standard and certain other loricariid cat- length) and weighed 1.4 kg. At time of capture this catfish was stationed at the fishes excavate and maintain entrance of a nest burrow containing eggs. (Photograph by L. G. Nico)

In this Issue: Non-Native Suckermouth Armored Catfishes in Florida: Description of Nest Burrows and Burrow Colonies with Assessment of Shoreline Conditions ...... 1

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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Nelson 2006). Although there is dramatic variation in body shape and dentition, as a group loricariids are characterized by a depressed body covered by large bony plates, a unique pair of max- illary barbels, and a ventral suctorial mouth (Covain and Fisch-Muller 2007). The sucker mouth of loricariids enables ad- herence to the substrate even in fast-flowing water and, in combination with specialized teeth, is an adaptation for feeding by scraping submerged substrates to consume algae, small invertebrates, organic sediments (e.g., detritus and mud), Figure 2. Nest burrows of loricariid catfishes in their native range in South and even wood (Schaefer and America: Cano Mavaquita, upper Orinoco River basin, Venezuela. Type locality Stewart 1993, Nico and Taphorn for Leporacanthicus triactis (Isbrücker et al. 1992). (Photograph by L. G. Nico) 1994, Yossa and Araujo-Lima

1998, Delariva and Agostinho associations between presence and 2001). Many members of the fam- abundance of burrows and bank Introduction ily are popular aquarium fishes instability. The suckermouth armored cat- used for controlling algae in tanks. The goal of the present study fishes (family Loricariidae) are an Several members of three lori- was to obtain baseline information extremely large and diverse group cariid genera (Hypostomus, Ptery- on the burrows of Pterygoplich- of New World freshwater fishes. goplichthys, and Ancistrus), all thys in Florida and to provide a The family includes six subfami- belonging to the subfamily Hypo- preliminary assessment of shore- lies, an estimated 90 genera, and stominae, have been introduced line conditions, including factors approximately 700 described spe- outside their native ranges. All or associated with bank stability and cies (Armbruster and Page 2006, most introductions into the wild erosion. Specific objectives in- Nelson 2006) with many more are likely linked to the ornamental cluded: 1) survey portions of se- species remaining to be described fish trade (Fuller et al. 1999, Nico lected rivers and canals in penin- (Reis et al. 2003, Birindelli et al. and Martin 2001, Vidthayanon sular Florida to determine the 2007). The natural distribution of 2005, Page and Robins 2006). number and location of loricariid this catfish family extends from Some of these non-native popula- catfish nest burrows; 2) measure the La Plata River of southern tions are firmly established in a and characterize burrow structures South America northward to Costa number of warm-climate regions and surrounding habitats; 3) iden- Rica of Central America, or from around the world. Among intro- tify shoreline features correlated about 35° S to 12° N latitude duced loricariids, members of the with the presence of burrows; and (Berra 2001). Members of the genus Pterygoplichthys are the 4) categorize bank condition and family may be found from low most widely introduced (Figure 1) erosion. To better understand the elevations up to 3,000 m and, de- with reproducing non-native popu- likely impacts associated with pending on species, adult lori- lations now documented as occur- these catfish and their burrows, cariids range in body size from ring in North and Central Amer- literature on the burrows of lori- relatively small, less than one or a ica, Asia, the Caribbean, and cariid catfishes and other animals few centimeters long, to over 1 m Hawaii. Pterygoplichthys are one was also reviewed. total length (Fuller et al. 1999, of the most abundant fish species

2 ANSRP Bulletin, Vol-09-1, March 2009 in certain habitats within their have not been determined. Collec- Hypostomus are known to exca- native range (Saint-Paul et al. tions or sightings of Pterygoplich- vate burrows along the sloped 2000) and introduced populations thys or Hypostomus have also shorelines of lentic and lotic habi- are large and, in some places, they been reported from other locations tats. However, there is little in- comprise a substantial proportion outside their native ranges, al- formation in the scientific litera- of the total fish biomass (personal though there is as yet little or no ture on the burrows and nesting observation. Leo G. Nico). evidence of natural reproduction. behaviors of these catfishes. This In North America Pterygop- For example, a specimen identi- shortage of information is surpris- lichthys are particularly common fied as P. disjunctivus was re- ing, given the broad distribution in certain drainages in the south- cently taken from the Asi River in and abundance of these catfishes ern United States in Florida and Turkey (Ozdilek 2007). within and outside their native Texas (Fuller et al.1999, Nico and Pterygoplichthys are medium ranges. Martin 2001) and in Mexico to moderately large fishes (Fig- This bulletin describes the bur- (Mendoza et al. 2006, Wakida- ure 1). Captured adults from intro- rows and burrow colonies of Kusunoki et al. 2007). Reproduc- duced populations generally mea- Pterygoplichthys based on field ing populations are also known sure 30 to 55 cm total length (TL) observations on non-native popu- from the islands of Oahu in Ha- although maximum size probably lations inhabiting canal and river waii (Sabaj and Englund 1999, exceeds 70 cm TL (Liang et al. systems of peninsular Florida. Pre- Yamamoto and Tagawa 2000), 2005; unpublished data, Leo G. liminary observations on active Puerto Rico (Bunkley-Williams Nico). Over the past 15 years, nests in clear-water stream habi- et al. 1994), and Jamaica (Jones Pterygoplichthys species in Flor- tats are included. A review of the 2008). In Asia, Pterygoplichthys ida have become increasingly literature on burrowing by lori- species have become increasingly widespread and abundant (Fuller cariids, burrowing by other fishes, widespread. The earliest docu- et al. 1999, Nico 2005). The au- and on burrowing by other non- mented records are from Singa- thors’ fish surveys, together with native aquatic species is also pro- pore (Lim and Ng 1990: misiden- reports and data from others (e.g., vided. The general goal of the re- tified as “Hypostomus;” also see Shafland et al. 2008) indicate that search on introduced Pterygop- Page and Robins (2006)) and In- these catfishes have rapidly ex- lichthys was to gather information donesia (Kottelat et al. 1993). panded their ranges and one or on invasive populations, especially More recently, members of the more Pterygoplichthys taxa now with regard to their natural history genus have been reported as estab- occur in all major drainages and and ecological effects. lished or possibly established in most minor drainages in the cen-

Japan (Nakabo 2002), Taiwan tral and southern part of the Flor- Methods (Liang et al. 2005), Thailand ida peninsula. In many waterways (Vidthayanon 2005), the Philip- Pterygoplichthys have become a Study Area pines (Chavez et al. 2006), Malay- major component of the aquatic sia (Page and Robins 2006), and community in terms of both num- Field work was conducted in Vietnam (Serov 2004, Levin et al. bers of individuals and fish bio- the central and south-central part 2008). An unidentified Pterygop- mass (personal observation, of the Florida peninsula between lichthys (= Liposarcus) was re- Leo G. Nico). Environmental im- latitudes 26° 59’N and 29° 13’ N ported as occurring in a river in pacts are not fully understood, but (Figure 3). Drainages surveyed for Costa Rica (Bussing 2002), but the where these introduced loricariids catfish burrows included parts of situation is dynamic. In late 2008, are abundant, their feeding behav- two artificial canals and four natu- William Bussing (personal com- iors and burrowing activities can ral rivers: St. Lucie Canal, Okee- munication) informed the authors cause considerable disturbance chobee Rim Canal, Peace River, that introduced loricariids were (Fuller et al. 1999, Yamamoto and Withlacoochee River, Alafia spreading rapidly in Atlantic slope Tagawa 2000, Hoover et al. 2004). River, and Oklawaha River. Tribu- drainages of Costa Rica, but the Among introduced loricariid cat- taries of a few of these waterways identity and number of species fishes, both Pterygoplichthys and were also investigated. Selection

ANSRP Bulletin, Vol-09-1, March 2009 3 of these waterways and reaches burrows were located, measured, documenting presence of burrows was based on several criteria: and assessed (Figure 3). To locate or other cavities in the bank. In 1) drainages were known or catfish burrows, waterways were most instances detection of one or strongly suspected of containing surveyed by boat. The shoreline, a few burrows led to discovery of Pterygoplichthys; 2) waterways including exposed bank and adja- additional burrows nearby. Geo- represented a diversity of habitat cent submerged shallows, was graphic coordinates of burrow types, ranging from artificial ca- visually inspected. All surveys sites were determined using a GPS nals to natural flowing systems; were conducted during good device. and 3) many of the waterways weather conditions and daylight The probability of detecting were already familiar and were hours. Field work was performed burrows varied within and among accessible by small boat. Nest bur- by two- or three-person crews sites due to local conditions (e.g., rows in a few of the waterways traveling in a small watercraft, water levels, water clarity, type chosen for the surveys had been either non-motorized canoe (upper and extent of shoreline cover). The observed during previous field Withlacoochee River) or by mo- likelihood of detecting burrows work. torized canoe or john-boat (all visually, especially in turbid wa- other sites). In general, the visual ters, is greatest when water levels Field surveys and hunt was focused along a single are low and many burrows are measurements bank during passage upstream and fully exposed above the water line. Field work was conducted in focused on the opposite bank dur- During 2006 water levels of many April and May 2006. During this ing the return journey down- rivers in peninsular Florida were period, selected reaches of the six stream. The search for burrows low throughout much of the spring waterways were surveyed and a consisted of traveling slowly (less and early summer. However, even range of exposed (above water than about 10 km/h) within about during low water some burrows line) and some submerged catfish 5 to 10 m from the targeted shore, are difficult to detect. In some reaches, large portions of the shore were obscured by dense vegetation (e.g., leafy shrubs, cypress stands). Some waterways had relatively clear water, facilitating the detection of submerged burrows. In contrast, it is likely that a higher proportion of submerged burrows went undetected in sites with turbid water. In addition, single burrows were more difficult to detect than groups of burrows and burrows below the water line or in root mats were also less likely to be observed than burrows in open areas. Sighting of any bank hole was immediately followed by close inspection of the sighted cavity to judge whether it was a catfish burrow and to determine if there were additional burrows in the vicinity. Some bank holes were degraded to such an extent that it was not al- Figure 3. Map of Florida showing the waterways and location of reaches sur- ways possible to confirm whether veyed for nest burrows of loricariid catfish during spring 2006.

4 ANSRP Bulletin, Vol-09-1, March 2009 the “burrow-like” structure was completely above the water line. devices (e.g., rangefinders). The created by Pterygoplichthys. The horizontal angle of burrow slopes of banks and burrows were These unconfirmed holes were entrance relative to water edge determined using a Swanson® noted but not included in subse- (i.e., shoreline) provided informa- magnetic angle finder and a quent burrow analyses. In the tion on whether a burrow tunnel 60-cm-long Stabila® 86 electronic field, each burrow site was as- was angled downstream (e.g., inclinometer and level (both in- signed a unique number and indi- 45 deg) and presumably away struments sealed in a plastic wrap vidual burrows of those sites cho- from direct current, oriented up- to prevent moisture damage). De- sen for close examination were stream (e.g., 135 deg), or perpen- pending on local conditions, angle also coded. To provide additional dicular (90 deg). If a submerged measurements were occasionally documentation, burrows, burrow burrow was occupied or guarded verified or determined in conjunc- colonies, and surrounding habitat by an adult Pterygoplichthys, the tion with other types of angle were photographed with a digital burrow was designated as active. finder devices (e.g., Empire® an- camera. In a few cases, burrow All other burrows, including dry gle finder and Sealey® stainless counts were verified and aug- burrows, were considered inactive steel protractor). Soil compaction mented by later examination of or abandoned. To document struc- was estimated with a DICKEY- photographs. ture, internal materials, and pres- john® soil compaction tester (0 to A wide variety of descriptive ence of eggs, the authors visually 600 psi). information and measurements inspected the interior of many bur- Soil composition analysis were recorded for most sites rows, in some cases with the aid of where nest burrows were found. lanterns. A few tunnels were Soil samples were collected Data collected from Pterygoplich- probed or opened by hand. from eight colonies. For each col- thys burrows included burrow In addition to measurements ony, a sample consisted of a com- length, maximum width at en- on individual burrows, quantita- posite taken from outside and ad- trance, maximum height at en- tive and qualitative data were re- jacent to the burrow entrance of trance, vertical and horizontal dis- corded for shoreline habitats two or more nest burrows. All tance to water edge (measured where catfish burrows were dis- samples were from exposed colo- from bottom of burrow entrance), covered. These included slope of nies (above water line), except for tunnel shape (e.g., single tunnel bank (at the entrance of each bur- two subsamples from a partly- versus bifurcated), burrow vol- row), height of exposed bank, active colony in the Oklawaha ume, average slope of tunnel, vegetative groundcover, and an River. Soil samples from each site horizontal angle of burrow en- estimate of bank stability/state of were saved in separate plastic bags trance relative to shoreline (down- erosion. Soil compaction was prior to analysis. All resulting soil stream = 0 degrees), compass measured on the bank adjacent to samples were provided to Univer- bearing perpendicular to the shore, each burrow entrance (length of sal Engineering Sciences, Inc., a burrow condition, burrow mois- probe to achieve 300 psi). At se- full-service geotechnical engineer- ture, and occupancy of burrow lected colonies, a composite sam- ing laboratory located in Gaines- (i.e., active versus abandoned). ple of soils was collected from all ville, Florida, to determine soil Because the majority of burrow or most of the burrows of the col- composition, including soil de- tunnels were somewhat triangular ony (see following section titled scription, natural moisture, and in cross section, burrow volumes “Soil composition analysis”). particle-size distribution. Particle were calculated by multiplying the Individual nest burrows, bur- size was determined by dry sieve average triangular area of the burrow colonies, and shoreline habi- analysis, using six sieves (mesh row entrances by burrow length. tats were measured by using a size numbers 4, 10, 40, 60, 100, Burrow moisture is an indica- combination of meter sticks, sur- and 200). Their procedures fol- tion of the amount of standing wa- veying rods, and tape measures, lowed those of the American ter in burrows at the time of meas- supplemented whenever necessary Society for Testing and Materials urement, ranging from completely with the use of an adjustable T- (ASTM): D422 Standard Test wet if fully submerged, to dry if square and other measuring Method for Particle-Size Analysis

ANSRP Bulletin, Vol-09-1, March 2009 5 of Soils; and D2216 Test Method vegetation when the burrows are as the amount of sediment re- for Laboratory Determination of submerged and actively used by moved by the crabs per volume of Water (Moisture) Content of Soil loricariid catfish. Consequently, a stream bank. Based on a modifica- and Rock. Excess soils from each measurement of vegetative cover tion of the methods used by Rud- of the samples that were not has only slight relevance in an nick et al. (2005), sediment re- needed for analysis were returned evaluation of the effects of Ptery- moval was calculated as the for possible future laboratory goplichthys burrowing. percent of soil removed by Ptery- analyses. The contributions of loricariid goplichthys (the sum of all vol- catfish burrowing to erosion and umes of burrows present in a col- Evaluation of the relation- sedimentation may be thought of ony) per the rectangular-shaped ship between burrows and as having both immediate and portion of the bank occupied by a bank stability long-term effects. Initial impacts colony (Figure 4). To investigate relationships from burrows are linked to the As part of the present study, between loricariid catfish burrows amount of sediment removed from the largest colony measured in and bank stability, the authors ex- shorelines during burrow excava- each waterway surveyed was se- amined the distribution pattern and tion. Long-term impacts such as lected for analysis. Burrow vol- density of burrows and analyzed compromised ability of banks to umes were calculated as described data on the shoreline habitats se- persist through the next flood re- above and no adjustments were lected for colony sites by Ptery- quire periodic monitoring of indi- made for old or degraded burrows. goplichthys. Attempts to quantify vidual sites and are beyond the Because the majority of burrows impacts were limited to evaluation scope of this study (refer to Cou- measured were either less than of small portions of shoreline con- per (2004) and Duan (2005) for 1 m in length or were angled so taining selected colonies and discussions on appropriate spatial that they did not head straight based on measurements taken dur- and temporal measurement scales back into the bank, all or most ing a single visit. According to Ott in the study of river bank erosion). burrowing was concentrated in the (2000), “…. a bank is stable if it In their evaluation of the im- 1-m depth of the bank. Therefore, does not change appreciably pacts of introduced Chinese mitten the available volume of soil for within a defined time frame.” Be- crab burrows, Rudnick et al. burrowing was the vertical and cause erosion is a dynamic and (2005) calculated erosion impact horizontal extent of the colony long-term process, occurring to varying degrees in all waterways, it is difficult to measure the contribution made by burrowing animals during a single season. Ac- cording to Lawler (1986), even where bank retreat is monitored, it is seldom easy to pinpoint the significant features of a site that are apparently promoting or retarding bank erosion. The situation is especially complex in streams and canals where water levels and flows change considerably over the course of a year (see Couper (2004) and Duan (2005)). Al- though the existence of bank vegetation is considered a stabilizing factor, most colony sites are Figure 4. Diagram of a burrow colony showing the three-dimensional portion of the shoreline used to calculate the relative amount of sediment removed by largely devoid of ground and leafy Pterygoplichthys.

6 ANSRP Bulletin, Vol-09-1, March 2009 multiplied by 1-m depth. For Table 1 example, if the lowest and highest Summary of the 2006 Loricariid Burrow Field Surveys (Burrow burrow openings were 2 m apart, counts do not include holes and other cavities if reasonable and the most upstream and most doubts existed concerning their creation. A burrow site is defined downstream burrows in the colony as a bank area within a single reach (<50 m shoreline) where all were 5 m apart, then the rectangu- burrows were in relatively close proximity. Burrow sites with multi- lar area was 2 × 5 m and the total ple burrows were considered colonies) Channel Length Burrow Sites Number Bur- volume of the involved bank Surveyed Detected rows Detected 3 would equal 10 m (Figure 4). Drainage Dates (km) [per km] [per km] Withlacoochee River April 24 & 27, 27.5 4 b 21 b Analyses and statistics (South)a May 5 [0.1] [0.8] St. Lucie Canal May 15 4.4 2 10 Multivariate ordination, corre- [0.5] [2.3] lation, and paired variable plots Lake Okeechobee May 15 4.6 0 c 0 c were used to explore possible rela- Rim Canal Peace River May 18 2 5 d 41 d tionships among the recorded ar- [2.5] [20.5] ray of burrow and habitat charac- Alafia River a May 19 11.25 2 21 teristics. PRIMER 6 software [0.2] [1.9] Oklawaha Rivera May 30 6.75 5 25 (Clarke and Warwick 2001) was [0.7] [3.7] used to create principal compo- Totals 56.5 18 118 nents analysis (PCA) plots of bur- [0.3] [2.1] a Survey included main channel and one or more tributaries. row dimension and soil composi- b Includes one colony site where individual burrows could not be counted because of extreme deg- tion data. Because burrow data radation. c Numerous exposed bank holes and undercuts were found in the Lake Okeechobee Rim Canal were collected in various units but it could not be determined if these represented old and highly weathered catfish burrows or ranging from angles in degrees to undercuts created by other processes. d Peace River census resulted in detection of at least five burrow colonies; burrows from two of the inches of penetration to achieve five colonies were not measured. soil compactions of 300 psi, these data were normalized prior to cre- attributed to the work of non- way had many exposed cavities ating the complete burrow PCA. native catfish, although it is likely along the upper edge of the canal’s When only height, width, and that at least some of these holes bank line, they were extremely length burrow parameters or soil were Pterygoplichthys burrows degradated and it could not be composition proportions were ana- from previous years. Generally, concluded with any confidence lyzed, the PCAs were done on un- these holes appeared to be highly that these undercuts had been cre- transformed data. degraded because of erosion or ated by Pterygoplichthys. Lake wave wash. It is probable that ad- Okeechobee and its adjacent ditional burrows were present but canals are known to contain large Results went undetected. For example, populations of Pterygoplichthys although a large colony was found (Nico 2005). Numbers and distribution in the Withlacoochee River, it was The 118 observed catfish bur- of burrows and burrow suspected that there were addi- rows were distributed among colonies tional burrows below water due to 18 sites, with the number of bur- Sampling information on the the geometry and composition of rows per site ranging from 1 to 16 six waterways surveyed is summa- the site’s bank. However, it was (mean = 6.6). Sites with multiple rized in Table 1. During the study impossible to view any additional burrows, where nearest burrows period, approximately 56 km of burrows in the deep and turbid were generally situated within a waterway were surveyed and water. few meters of one another, were 118 burrows considered to have Burrows were detected in five considered colonies. Among these, been excavated by Pterygoplich- of the six waterways surveyed 15 burrow sites consisted of at thys were documented. In some (Figure 3, Table 1). The only ex- least four burrows. In two other waterways, holes above the water ception was the Lake Okeechobee cases, sites consisted of only two line could not be definitively Rim Canal. Although that water- burrows. Only one site held an

ANSRP Bulletin, Vol-09-1, March 2009 7 isolated burrow considered to be colonies were much more evident River, a series of burrows were made by Pterygoplichthys. A few in upstream portions of natural present along a single sharp outer isolated cavities at other sites were drainages where there were bend of the river. At this site either highly degraded or so steeper banks and greater fluctua- docks and a boat ramp widely irregular (e.g., odd-shaped cavity tions in water levels. In down- separated the burrows present into under a large stone) that they were stream portions of rivers and other two main groups. not treated as Pterygoplichthys reaches where banks were low or In most colonies, some bur- burrows nor were they included in almost nonexistent, burrows were rows were grouped together. the analyses. either absent or went undetected. Among these clumped burrows, All detected burrows were lo- Individual burrow colonies en- the distance between adjacent bur- cated along the river and canal compassed relatively small sec- row openings was typically less banks. No burrows were observed tions of bank. The horizontal ex- than 1 m. In some cases only in the bed of waterways, although tent (i.e., alignment parallel to about 25 cm of soil separated ad- some waterways were deep and shoreline) of colonies varied jacent burrow openings. In terms turbid and any bottom burrows widely, ranging from one or a few of vertical distribution, the lowest would have been obscured. Simi- meters for small colonies, to well burrow opening was typically larly, it is conceivable that bur- over 15 m for colonies composed never less than about 1.5 m below rows were present in stream bot- of many burrows. In contrast, the the highest burrow within a col- toms where there were numerous vertical layouts of most colonies ony. Due to the water level at the limestone boulders and ledges. Of were within a 1-m stratum of time sampled, exposed burrows the burrows detected, 85 (72 per- shoreline. In general, burrows were located up to 1.35 m above cent) had entrances that were ex- within colonies were relatively and 4.7 m horizontally out from posed above the water edge, either contiguous, but in some cases the water’s edge. These two pa- entirely or partially (>50 percent dense masses of tree roots and rameters were positively corre- of burrow entrance above the wa- other structures subdivided the lated and largely described the ter line). Some colonies included a colonies into subgroups. For ex- overall bank slope at sampling combination of both submerged ample, in the Withlacoochee sites (Figure 5). and exposed burrows. Burrows were not distributed evenly within or among waterways (Table 1). The section of the Peace River that was sampled had the highest densities of burrow sites (2.5 per km) and burrows (20.5 per km). This area was mostly exposed banks that were suitable for burrowing and ideal for detecting burrows at the low water stage during the site visit. In natural rivers, all observed burrow colonies were located along the outer bends of channels, but in most surveyed reaches only a relatively small proportion of cut- Figure 5. Relationship between vertical and horizontal distances from Pterygop- banks contained burrows. Burrows lichthys burrows to waterline (adjusted R2 = 0.74, p<0.001). The 0-horizontal were also absent from certain sites line represents the waterline. Burrow points above this line were those whose where the conditions, based on entrance was completely above the water. The 0-vertical represents the water’s edge. As shown in this figure, most of the observed nest burrows were exposed characteristics of sites with bur- because of low water and most of these were within 2 m out from the water’s rows, seemed suitable. Burrow edge, but less than 0.5 m above water surface.

8 ANSRP Bulletin, Vol-09-1, March 2009 Burrow characteristics Table 2 Complete measurements were Dimensions of Pterygoplichthys Burrows Measured in Five River taken for 63 burrows; 58 of these and Canal Systems, Florida Standard were considered to be in sufficient Dimension n Minimum Maximum Average Deviation condition (e.g., tunnel had not Bank slope (degrees) 61 30 92 64.4 17.5 completely collapsed) to be in- Burrow vertical position (cm to 74 -140 135 28.7 56.2 cluded in statistical analyses. Ad- water surface) ditional burrows were examined in Burrow horizontal position (cm to 63 -125 470 103.6 124.6 water edge) the field, but only partial meas- Burrow height - floor to roof (cm) 60 7 27 14.2 4.2 urements or other information at entrance were recorded for these structures. Burrow width (cm) at entrance 62 11 45 21.0 6.8 Most burrows (61 of 63 burrows Burrow tunnel length (cm) 63 20 130 77.5 27.5 3 examined) were rather simple Burrow volume (cm ) 60 1,960 58,630 12,911 10,476 Burrow slope (along tunnel) (de- 60 -18 11 -8.0 7.1 structures, consisting of a single grees) opening and a relatively straight Burrow angle (degrees, down- 60 15 160 81.7 24.6 tunnel without marked bends or stream = 0) bifurcations. However, there were Soil compaction – inches of rod to 55 0.5 28 10.1 8.3 achieve 300 psi two exceptions. One burrow was bifurcated (Y-shaped), having a explain the two-mouthed tunnel 130 cm (mean = 77 cm) in length, single entrance and then splitting described above. and the dimensions of the entrance near its midpoint into two sepa- The entrance and tunnels of ranged from 11 to 45 cm (mean rate, blind chambers. In contrast, most burrows were somewhat tri- = 21 cm) in width, and 7 to 27 cm another burrow structure had two angular in cross section, although (mean = 14 cm) in height openings, its two entrance tunnels some were arched and a few oval (Table 2). Heights of burrow en- converging into a single interior or rounded at the mouth. In some trances were consistently less than tunnel. Based on its geometry, the cases, the burrow geometry was entrance widths, with height aver- two entrances tunnels were proba- partly determined by adjacent aging 66 percent of width. Burrow bly excavated by different catfish structures (e.g., tree roots). Bur- height and width were positively that dug into a common end. row tunnels ranged from 20 to correlated (Figure 6). The interior slope of individual tunnels typically angled gently downwards, ranging from -18 to 11 degrees (mean = -8 degrees) (Table 2). Consequently, burrows with entrances slightly above the water surface tended to be dry at the opening but contain water to- ward the rear. Horizontal alignment of tunnels, relative to the shoreline edge, varied even within colonies, with some tunnels angled downstream, some upstream, and some approximately perpendicular. The average alignment was slightly downstream (81 deg). The proximity of tunnels in some colonies and the wide variation in tunnel horizontal alignment likely Figure 6. Relationship between Pterygoplichthys burrow entrance height and width (adjusted R2 = 0.49, p < 0.001).

ANSRP Bulletin, Vol-09-1, March 2009 9 Variation in both tunnel length and volume was likely related, at least in part, to burrow age and condition (also see later section Evaluation of Bank Stability and Erosion). For example, some of the largest burrows were either active nests or considered to be only recently abandoned. The four Oklawaha River burrows had the largest interior volumes and also were the deepest below the water surface (Figure 7). Three of these were also the only active burrows measured. In contrast, exposed burrows located high on the bank tended to be smaller, presumably a result of bank erosion. In at least one case, it appeared that the cat- Figure 7. Relationship between burrow volume and vertical distance to water fish had begun excavating a bur- surface. Note that the three Oklawaha burrows with the largest volumes were row but after only a few centime- active with catfish tending nests. ters of digging, abandoned the unfinished burrow. The complete burrow dimension PCA plot (Figure 8) revealed that although burrows were sampled across the state, there was no distinct pattern of burrow dimension with sampling site. Only four Oklawaha River burrows clearly separated from the rest of the sites. Three of these four burrows were active, each occupied by an adult Pterygoplichthys guarding the burrow entrance. The first principal component axis (PC1) accounted for 33 percent of variation and was associated with height and width of burrows and vertical distance to water surface. PC2 was associated with burrow length, burrow slope, and angle relative to flowing water, but only accounted for an additional 22 percent of variation. Figure 8. Principal component analysis plot of Pterygoplichthys burrow dimen- When the PCA was limited to sions from Table 2 (excluding volume) measured at 58 burrows in five river and burrow height, width, and length, canal systems in Florida with principal component vectors superimposed. PC1 the first two principal components is associated with height and width of burrows and vertical distance to water surface. PC2 was associated with burrow length, burrow slope, and angle rela- accounted for 99 percent of the tive to flowing water. variation (Figure 9). PC1 was

10 ANSRP Bulletin, Vol-09-1, March 2009 age. However, even in exposed areas the vegetation was relatively sparse, probably due to a combination of periodic inundation and scour. Parts or all of some colonies were closely associated with the large roots of riverside trees (e.g., cypress). In these places, root mass was partially exposed along the bank and burrows had been excavated among the large roots. In the St. Lucie Canal, some of the burrows were along the uppermost edge of the rip rap rock. Land habitat within or imme- Figure 9. Principal components analysis of burrow height, width, and length diately adjacent to where burrow among 58 burrows in five Florida river systems. PC1 is associated with increas- colonies were present varied. ing length, while PC2 is associated with increasing height and width. Habitat included narrow bands of associated with increasing length, The height, cross-sectional gallery forest, cattle pasture, old while PC2 was associated with shape, and general slope of river fields, riverside clubhouses and increasing height and width. and canal banks with colonies other residences with boat docks, Again, the active Oklawaha bur- were also diverse. The cross- and a mix of other land uses. Most rows separated from other sites. section morphology of most banks waterway reaches surveyed were was not uniform, often irregularly located in rural or low-density Burrow colony habitats shaped and with a rather stair- residential areas. None of the sites Habitats with burrow colonies stepped profile at some sites. In was urban. were fairly diverse, evidence that stair-stepped banks, burrows were Soil characteristics of bur- Pterygoplichthys are relatively usually situated in one or more of row colony sites flexible in their choice of sites for the strata with the greatest incline. Analysis of particle sizes indi- burrow construction, spawning, The height of exposed banks with cated that the soil composition and nesting. Burrows were present burrows ranged from less than 1 m among the eight colonies sampled in small streams (e.g., Alafia to over 3 m. In most sites the bur- was largely a mixture of fine and River), moderate-sized streams, rows were located well below the very fine sands and silts-clay and artificial canal habitats, repre- top of the bank. In contrast, a se- (Figure 10). Based on the classifi- senting an array of water types and ries of cavities—possibly created cation of the Soil Science Society flow regimes. In both canals and by Pterygoplichthys—along the of America, soil textures were rivers, burrows were located on shore of the Lake Okeechobee sandy-clay-loams (four sites), sloping channel banks and all ap- Rim Canal were found within the clays (two), sandy-clay (one), and peared well within the “bankfull uppermost meter of the bank. sand (one). Soil composition PCA stage” limits of respective water- The portion of the banks with showed that sites varied consid- ways. In natural rivers, all colo- burrows typically contained few erably (Figure 11). Alafia River nies were found along the outer leafy or herbaceous plants. How- and Peace River Site 4 both had bends of channels, although the ever, as is normal in riverine envi- large amounts of clay, Oklawaha geometry of bends selected varied ronments, herbaceous and some River and Peace River Site 1 had from slight meanders to sharp. In small woody plants were found medium and coarse sand, while canals, burrows were found along sprouting within burrow colonies the other sites had mostly fine and straight sections where much of exposed by low water. As would very fine sands. PC1 accounted for the bank was exposed and steep. be expected, the longer the expo- 76 percent of variation and was sure, the greater the plant cover-

ANSRP Bulletin, Vol-09-1, March 2009 11 sidered relevant to an analysis of Pterygoplichthys burrows for a variety of reasons. Minimum values may be indicative of sites where the soil density was such that burrows were unlikely to collapse. Low values were also thought to be indicative of soils more likely to erode. Maximum values were indicative of soil that was relatively dense, but not dense enough to prevent successful excavation by Pterygoplichthys. There are a few caveats associated with the results. Most measurements were made on dry bank sur- faces, adjacent to burrows that were exposed. Upon hydration, the Figure 10. Soil composition of samples taken from eight different Pterygoplich- soil compaction properties would thys burrow sites in five river and canal systems in Florida. differ from exposed, dry banks. Some exposed banks had been baked in the sun, so that an outer crust was formed making it difficult to penetrate with the probe. Evaluation of bank stability and erosion General observations on the nest burrow sites indicate that Pterygoplichthys generally excavate their burrows in shoreline habitats of rivers and canals already prone to erosion (e.g., outer bends of meandering rivers, steep Figure 11. Principal component analysis plot of soil composition associated with banks often composed of sandy- Pterygoplichthys burrows in five river and canal systems in Florida with com- clay-loams with sparse vegetation ponent vectors superimposed. PC1 is associated with increasing silt/clay and cover). They typically select rela- decreasing fine sand proportions. PC2 is associated with decreasing propor- tively steep portions of banks with tions of coarse sand. Soil texture designations follow the classification of the Soil Science Society of America. soils friable enough to dig into, yet stable enough to not collapse eas- associated with increasing silt-clay sions of burrows (Figure 9). Bur- ily. Such bank conditions make it and decreasing fine sand propor- row volume was associated with easier for Pterygoplichthys to ex- tions. PC2 was associated with degree of submergence and occu- cavate, but also more likely to decreasing proportions of coarse pation by catfish. slump or erode. sand and accounted for an addi- Soil compaction measurements Average burrow volume was tional 22 percent of variation. ranged from 0.5 to 28 (average calculated at 12,911 cm3. Thus for Despite differences in soil compo- 10.1) in. of probe penetration to a typical colony of 12 burrows, sition among sites, there appeared achieve 300 psi (Table 2). Measur- 154,932 cm3 or about 0.15 m3 of to be little difference in the dimen- ing of soil compaction was con- soil was removed. In evaluating

12 ANSRP Bulletin, Vol-09-1, March 2009 the amount of sediment removed between burrow volume and dis- the base of steep banks within from an area of bank, analysis was tance (vertical) to water surface, a or just above existing rip-rap restricted to colonies with the possible explanation for differ- revetment (Figure 13). The up- highest number of burrows in each ences in observed volumes of ac- per portions of much of the of the five waterways with bur- tive versus abandoned or even ex- shoreline, unprotected by rip- rows. Based on that data, Ptery- posed burrows is provided in rap, appeared highly unstable. goplichthys removed an estimated Figure 12. The assumption is that Although the burrows probably 1 to 4 percent of sediment per rec- burrows above the water and other were contributing to bank in- tangular (1-m deep) volume of abandoned burrows were, prior to stability, their contribution al- bank through their burrowing ac- erosion, as large as the active bur- most certainly was low relative tivities (Figure 4, Table 3). Be- rows discovered in the Oklawaha to erosion caused by wave ac- cause sites were not monitored River. tion, in particular, the incredi- over time, a distinction was not bly forceful waves that strike Overview of waterways made between ages of burrows. the shore whenever high-speed surveyed The relative amount of sedi- boats and yachts pass (a com- ment removed would be greater if Brief accounts for each of the mon event). Burrows in high- calculations are based on the aver- six waterways surveyed are as fol- traffic waterways could act age volume of active burrows. For lows (Figure 3): synergistically to increase ero- example, the volumes of each of • St. Lucie Canal. The St. Lucie sion. Two burrow colonies the three burrows in the Oklawaha Canal, 64 km long, connects were discovered during the River with guarding males present Lake Okeechobee with the At- survey. All detected burrows (presumably also maintaining the lantic Ocean. The water in the were exposed, although some burrows), ranged from over 0.04 canal is relatively turbid. Bur- of the burrows in the larger to nearly 0.06 m3 (Figure 7). As row sites examined in the St. colony were near the water’s suggested by this relationship Lucie Canal were on or near edge and subject to waves. • Lake Okeechobee Rim Table 3 Data from Colonies with Highest Number of Burrows in Each of the Canal. This artificial water- Five Waterways Sampled (Vertical extent of colony is the distance way, composed of a number of between the highest and the lowest burrows relative to water sur- unconnected segments, extends face (negative numbers indicate entrance floor of burrow was be- along large sections of the low water). Horizontal extent is the distance between the most outer border of the 230-km upstream and most downstream burrow. Summed burrow volume long, high earthen levee that is the total volume of all burrows at site (see Methods for surrounds Lake Okeechobee. calculation)) Besides the occasional small- Waterway system Withlacoochee St. Lucie Peace Alafia Oklawaha boat wake, these canals are Site field number LGN 06-34 LGN06-42 LGN06-51 LGN06-55 LGN06-59 very low-energy systems, more Maximum vertical 1.35 0.6 0.24 0.36 0.02 similar to lake habitats than distance (m) riverine environments. In the Minimum vertical 0.84 0.16 -0.59 0.12 -1.4 distance (m) area that was sampled, along a Vertical extent of 0.51 0.44 0.83 0.24 1.42 northeast side of the lake, the colony (m) canal is separated from the toe Horizontal extent of 14.5 11.7 4.9 18.3 7.28 colony (m) of the levee by a wide and flat Summed burrow 0.11 0.11 0.17 0.15 0.18 open shore area. Water levels at volume (m3) Available bank vol- 7.40 5.15 4.07 4.39 10.34 the time were moderately low, ume (m3) exposing undercuts and fissures Proportion of bank 0.01 0.02 0.04 0.04 0.02 along the upper part of the low volume Number of burrows in 11 8 16 14 5 bank on the levee side of the colony canal (Figure 14). However, the Burrow density (#/m2) 1.49 1.55 3.93 3.19 0.48

ANSRP Bulletin, Vol-09-1, March 2009 13

Figure 13. Portion of a burrow colony on the St. Lucie Ca- nal showing three exposed burrows, indicated by red flags (Field # LGN 06-41). Here burrows are closely associated with rip-rap revetment and the rock apparently affords burrows protection from the heavy wave wash of passing boats. (Photograph by L. G. Nico)

Figure 12. Bank profile and longitudinal section of a Pterygoplichthys burrow. Drawing shows possible se- quence of events over time as water levels drop and bank erodes: a) high water period showing active burrow with eggs being guarded and burrow structure maintained by Figure 14. Photograph of a portion of the west shore of the adult catfish; and b) same site during low water, after nest Lake Okeechobee Rim Canal just north of the St. Lucie has been abandoned and exposed to air. As a result of Canal. Many highly eroded holes such as these were scat- lack of maintenance by catfish and continued exposure of tered above the waterline and could not be definitively burrow to wave wash and other forces, the bank has attributed to the work of Pterygoplichthys. A portion of the eroded, causing the burrow structure to degrade and its levee surrounding the lake is in the background. (Photo- length to become reduced. graph by L. G. Nico)

extreme degradation of these the eroding bank and the toe levee. The lake shore was pro- holes made it impossible to of the levee is considerable tected by rip-rap rock and a discern that these undercuts had (probably much greater than brief tour revealed no evidence been created by Pterygoplich- 50 m). Consequently, even if of burrows along its margin. thys. Lake Okeechobee and ad- some or all of these burrows • Peace River. The 171-km long joining waters are known to were created by Pterygoplich- Peace is a moderate-sized contain large populations of thys, the associated erosion did stream with tannin-stained wa- Pterygoplichthys (Nico 2005) not appear to be an immediate ter and moderate water clarity. and dried carcasses of Ptery- threat to levee integrity. The Although fed by a few springs, goplichthys were found along authors walked a small portion most of its volume is from the canal’s bank. In the reach (<100 m) of the lake shore other sources. The river is surveyed, the distance between along the interior part of the characterized by sharp bends

14 ANSRP Bulletin, Vol-09-1, March 2009 and consists of moderately burrows, the river was at very • Alafia River. The 40-km long steep banks throughout most of low water stage and large num- Alafia is a small meandering the reaches surveyed. Fishes in bers of Pterygoplichthys were stream with tannin-stained wa- the Peace River have been sam- seen in shallow portions of the ter and moderate water clarity. pled on numerous occasions. river. The low water also en- Some tributaries, such as Buck Pterygoplichthys were first abled documentation that the Creek, are spring fed with clear captured in the system in 1995 nest burrows of this species are water. During the survey, the and were relatively common in common in the system Alafia was at low water stage. subsequent fish collecting sam- (Figure 15). Pterygoplichthys were common ples. During a 2006 survey for and easily sighted in most shallow sections of the river. Inter- estingly, another herbivorous fish, the native striped mullet Mugil cephalus was also common. Although a few isolated cavities were observed, some possibly nest burrows of Ptery- goplichthys, the first burrow colony was located upstream in an area with steep banks (Figure 16). • Withlacoochee (South) River. The 252-km long Withlacoo- chee (South) is a natural meandering river of moderate size. Although the main channel is naturally tannin stained, over recent years water clarity in the main channel of the Withla- coochee River has declined considerably. One of its major tributaries, the Rainbow River, is a spring-fed stream with clear water running through low topography and flush with vegetation. The lower reaches of the Withlacoochee in the vicinity of Dunnellon, together with the lower Rainbow River, are impounded. Near the town of Dunnellon the elevation is low and there are few exposed banks. Although Pterygoplich- Figure 15. Burrow colonies on the Peace River. Upper photograph: Portion of thys are occasionally sighted in colony showing four exposed burrows indicated by red flags. This colony includes exposed and submerged burrows, although the submerged burrows did the Rainbow River, no evi- not appear to be active nests. Lower photograph: Portion of this colony encom- dence of burrows was found. In passed tree roots and some burrows were hidden among the large roots. Such the main channel of the With- burrows would likely pass undetected if the river was surveyed during higher lacoochee no catfish burrows water and the burrows were submerged. (Photographs by L. G. Nico)

ANSRP Bulletin, Vol-09-1, March 2009 15

were located until traveling Follow-up studies are currently investigation of burrow colonies much farther upstream, where underway in the Oklawaha and its and Pterygoplichthys behavior. exposed high ground was more tributaries, part of a more detailed common (Figures 17 and 18). Three of the burrow colonies were located along bends where there were residences. At two of these sites the burrows were situated around boat docks and there was clear evidence of erosion. One of the sites included in the 2006 survey contained active burrows in 1997, indicating that the same sites are used for spawning over multiple years (Figure 19). Although excavation of burrows among tree roots is not uncommon, in the Withla- coochee burrows were discovered among the roots of cypress (Figure 20). Another burrow colony was highly degraded, Figure 16. A portion of a large burrow colony on the Alafia River showing located along a shore within a 10 exposed burrows indicated by red flags. This colony was constructed in soil of high clay content and the shore seemed to be relatively stable. (Photograph pasture and much of the river by L. G. Nico) bank apparently trampled by cattle. • Oklawaha River. The 121-km long Oklawaha is a low- gradient, meandering stream. The main channel has tannin- stained waters with moderate clarity. Its tributary, the Silver River, is spring-fed and has clear water. Because the Okla- waha is primarily groundwater fed, it was not as low as other sampled rivers. The Oklawaha was the only drainage where submerged nests that were being actively guarded by adult Pterygoplichthys were observed (Figure 21). The authors were able to photograph and Figure 17. Burrow Site #1 on the Withlacoochee River (Field # LGN 06-34). This collect an adult male and also colony included exposed burrows, some located upstream and others down- recover the guarded eggs at one stream of the private boat dock. Eleven burrows were measured, but additional colony site (Figures 1, 22, and burrows were later seen immediately downstream and it was suspected that the colony also included a few burrows still submerged (Photograph by L. G. Nico) 23).

16 ANSRP Bulletin, Vol-09-1, March 2009

Discussion

Descriptions of suckermouth armored catfish burrows in the literature Based on a review of the literature, the excavation and maintenance of burrows by certain loricariid catfish species is rather unique among primary freshwater fishes. The complex behavior of creating and maintaining burrows by Pterygoplichthys and certain other loricariids is most similar to that of several marine fishes. As with Pterygoplichthys, their burrows are also generally used for spawning and nesting habitat. The reproductive behavior Figure 18. A portion of Burrow Site #1 on the Withlacoochee River showing five among loricariids, including the of the 11 exposed burrows actually measured (Field # LGN 06-34). Typical of sites selected for spawning and many Pterygoplichthys colonies, the burrow openings are triangular and some nesting and the extent of parental burrows are closely grouped. (Photograph by L. G. Nico) care of eggs and young, is very diverse and rather complex (Covain and Fisch-Muller 2007). Use of natural cavities (e.g., hol- low logs) for spawning and nesting is practiced by some loricariids, for example, Ancistrus and Loricaria, among others (Eric et al. 1982, Sabaj et al. 1999, Covain and Fisch-Muller 2007). However, the excavation of nesting burrows among loricariids appears restricted to certain genera and species within the subfamily Hypostomi- nae and is typical of members of the genera Hypostomus and Ptery- goplichthys. Nevertheless, the published literature is incomplete. For instance, it is not known with Figure 19. Photograph showing upstream portion of Burrow Site #2 on the With- certainty if all species in these two lacoochee River (Field # LGN 06-35). This burrow colony was situated on the genera excavate burrows. In addi- outside of a sharp bend near decks and boat ramps of private residences. The eight burrows detected at this site were degraded, most had partially filled with tion, although some loricariids are silt and some had already collapsed (red arrows indicate location of two of the considered cavity spawners, in- eight burrows). Two active burrows submerged and guarded by adult catfish cluding some non-hypostomine were observed at this site by LGN during a visit in June 1997, indicating that the taxa (Covain and Fisch-Muller same colony sites are used over multiple years. (Photograph by L. G. Nico)

ANSRP Bulletin, Vol-09-1, March 2009 17 responsible for the actual excavation of the burrows. Although not observed, some have speculated that L. triactis might simply be using bank holes excavated by cavity-nesting birds, occupying already excavated holes after river levels rise during the rainy season and the burrows become submerged (see http://www.scotcat .com/factsheets/leporacanthicus_ triactis.htm). There is a fair amount of literature on the reproductive biology of loricariid-hypostomine catfishes (e.g., Sabaj et al. 1999, Suzuki et al. 2000, Liang et al. 2005), but relatively little information has been published on the Figure 20. Small burrow colony, highly degraded, on the Withlacoochee River burrows of these fishes. This is (Field # LGN 06-36). This site was within a reach of live and dead cypress. The site with burrows was one of the few areas in this part of the river with exposed surprising given the fact that bur- bank. If any burrows were within the reaches with dense cypress roots, they rows are most likely an integral would have been difficult or impossible to detect. (Photograph by L. G. Nico) part of reproduction for many hypostomines. In their review of the modes of fish reproduction, Breder and Rosen (1966) refer- enced only two papers that mention loricariid burrows. The first was a publication by Carter and Beadle (1931) describing field investigations in the Paraguayan Chaco. In their account on “Ancis- trus anisitsi” (now recognized as Pterygoplichthys anisitsi), the only mention of burrows is the statement: “The eggs are laid in holes in banks at the edge of the swamp …” [pg. 348]. In a subsequent pa- per, Azevedo (1938), based on discussions with local fishermen, reported that “Plecostomus ple- Figure 21. A portion of a small burrow colony in the Oklawaha River drainage costomus” [= Hypostomus ple- consisting of one exposed burrow (see red flag, center right) and four submerged costomus] deposits its eggs in burrows containing eggs and guarding adults (Field # LGN06-59). (Photograph holes. In neither of the cases men- by L. G. Nico) tioned above did the authors dis- 2007), it is not known how many Leporacanthicus triactis, has been cuss the possibility that these cat- other loricariid genera include bur- found to occupy burrows (Fig- fishes were responsible for the row excavators. For example, at ure 2; Isbrücker et al. 1992). actual excavation of the nest holes. least one other hypostomine, Adults of this species are likely

18 ANSRP Bulletin, Vol-09-1, March 2009 a species of Hypostomus (reported as Hypostomus plecostomus) inhabiting small ponds in Florida used to cultivate ornamental fish. He noted that, given suitable “turf,” Hypostomus constructed burrows into the side of a pool. Grier reported that each burrow normally consisted of a single opening but interiorly the burrow subdivided into three or four different tunnels. The author noted that the burrows extended “3– 4 feet” (0.9–1.2 m) and were parallel to the surface of the pond. According to Grier, these tunnels rarely extended upwards or down- Figure 22. Adult Pterygoplichthys stationed at the entrance of a burrow in the Oklawaha River drainage. Native Lepomis species, such as the Redbellied Sun- wards, over or below, the burrow fish (Lepomis auritus) seen here on right, have been observed in the vicinity of opening (i.e., the burrows were burrows, possibly nest robbers waiting for opportunity to prey on Pterygoplichthys generally horizontal). In a subse- eggs and young (Field # LGN06-64). The burrow in the photograph is part of a quent publication, Burgess (1989) colony included in an ongoing study on Pterygoplichthys behavior and burrow also briefly described the burrows activity. (Photograph by Travis Tuten) created by Hypostomus raised in Florida aquaculture ponds, reiter- ating much of the same information previously provided by Grier (1980) but without citing a source. In slight deviation from Grier, however, Burgess reported that tunnels were 1.2–1.5 m deep. Garcia-Pinto et al. (1984) investigated the reproductive biology of a loricariid catfish inhabiting artificial ponds at an aquaculture station in Zulia State, northwestern Venezuela. The researchers reported that the species was native to the area, the Lake Mara- caibo basin, and referred to it by the common name “Armadillo Pintado” and scientific name Hypostomus watwata (accord- Figure 23. Egg mass recovered from Pterygoplichthys burrow. The guarding ing to the loricariid expert adult from this nest is shown in Figure 1. Jon Armbruster, Hypostomus vil- larsi is probably the valid name One of the first widely- (1980). Publishing his findings in for this species). Garcia-Pinto and circulated articles that included an aquarium magazine, Grier his colleagues provided a brief data on the excavation of burrows briefly described and provided a description of the sites and mor- by loricariids is that of Grier few photographs of the burrows of phology of burrows excavated by

ANSRP Bulletin, Vol-09-1, March 2009 19 this catfish and, of additional im- pond bottom cleaned of debris. and mud substrates along the res- portance, included a photograph of The inner part of the cleared area, ervoir shoreline. He noted that the a nest entrance and drawings nearest the burrow openings, con- basal edges of abandoned tilapia showing dorsal and longitudinal sisted of excavated material and nests were favored, possibly be- views of different nests. Each of the outer part of the cleared area cause the relatively soft mud with- the ponds holding the catfish consisted of the clean or exposed in these sites permitted easy bur- measured 0.25 ha, and the pond hard clay bottom. Garcia-Pinto et rowing. During the study, the en- bottoms and surrounding dikes al. (1984) further observed that trance opening of 860 burrows were composed of clay. It was male and female catfish entered or were measured and 18 entire tun- noted that male catfish selected an exited any one burrow by way of a nels were excavated to obtain in- area either on the pond bottom or single opening. They added that formation on burrow dimensions. bank and, after finding a suitable other members of the subfamily In contrast to what Grier (1980) spot, used their pectoral fins to Hypostominae populating natural had described for Hypostomus remove any debris and loose mud tributaries within the Lake Mara- burrows in Florida, Devick (1988) so as to expose the underlying sur- caibo basin exhibited reproductive reported that the burrows of Ptery- face of compact clay. According behavior similar to that of the cat- goplichthys in the Hawaii reser- to the researchers, the catfish fishes inhabiting the research sta- voir were highly irregular and would then dig a burrow in the tion’s artificial ponds. typically sloped downward. In cleared area (unfortunately, the Among the literature exam- some sites, crayfish burrows were authors do not describe the actual ined, the most detailed descrip- connected to the catfish burrows. excavation process, for example, tions of loricariid catfish burrows Devick assumed that the crayfish whether or not fish used their pec- are included in two unpublished burrows were sometimes enlarged toral fins, rasping teeth, or a com- reports produced by the Hawaii by the catfish when creating their bination, to dig the burrow). Department of Land and Natural own tunnels. In areas where cat- Garcia-Pinto et al. (1984) Resources and are based on inves- fish burrows were numerous, the stated that the completed burrow tigations of non-native loricariids shafts sometimes connected, al- was almost cylindrical, with an present on the island of Oahu though the connecting of two tun- average length of 81.5 cm and an (Devick 1988, 1989). The most nels was thought by Devick to be opening entrance averaging be- significant of these documents is inadvertent. tween 17.3 and 21.9 cm in diame- Devick’s 1988 report containing Devick described the tunnels ter. The interior tunnels varied, results of field studies on a large as having basal grooves, appar- some consisting of only a single population of Pterygoplichthys, ently formed by the extended pec- tunnel but others were bifurcate. identified as P. multiradiatus, toral fins of the catfish. Conse- Burrows excavated on the pond established in Wahiawa Reservoir quently, in cross-section, the bur- bottom were described as having a (a 141.6-ha impoundment also rows were somewhat triangular in slight incline with respect to the known as Lake Wilson). The re- shape. The dimensions of 18 bur- horizontal pond bottom, whereas port includes a series of photo- rows examined ranged from 48 to burrows excavated in the sur- graphs and drawings of the catfish 107 cm (mean = 80 cm) long and rounding dike were reportedly and their burrows. During late 10 to 26 cm (mean = 14 cm) wide. perpendicular to bank edge and, August 1987, when the water level These were excavated by catfish presumably, horizontal. One dia- was low, a survey revealed 3,746 ranging in size from 21 to 51 cm gram by the researchers shows as exposed nests (above water line) (mean = 28 cm) long. Devick many as three nest burrows in very in the reservoir. However, this (1988: Figure 10) presented a close proximity, with adjacent number was considered to be a graph that provided information burrow openings within 10 cm or low estimate because many bur- on the number of tunnels and tun- less of one another. In addition, all rows hidden in grass or other nel width. Based on that graph, three burrow openings were situ- cover went undetected. Devick entrance width of 860 burrows ated within a circular area (about (1988) stated that the burrows ranged from about 3.5 to 27 cm 1.5 to 2 m in diameter) on the were present in a variety of clay and averaged about 13 cm. The

20 ANSRP Bulletin, Vol-09-1, March 2009 small size of some burrows (less Gobiidae–gobies (Ishimatsu et al. formed likely depends upon the than 4 cm wide) would indicate 1998, Itani and Uchino 2003, consistency of the sediment (see that even relatively small juvenile Gonzalez et al. 2008); Malacan- Atkinson and Taylor 1991). In ad- Pterygoplichthys excavate bur- thidae–tilefishes (Able et al. 1982, dition and in contrast to species rows, but Devick does not discuss Twichell et al. 1985); Opistog- that actively burrow, many other this subject (based on Devick’s nathidae–jawfishes (Colin 1973); fishes use natural and artificial own data on the relationship be- Pholidichthyidae–convict blenny cavities (e.g., many ictalurid cat- tween burrow width and catfish (Clark et al. 2006); Stichaeidae– fishes) or occupy burrows created length, a 4-cm-wide burrow would pricklebacks (Nash 1980); by other organisms (e.g., Randall have been created by a catfish Serranidae–groupers (Jones et al. and Earle 2006). approximately 8 cm long). 1989); and others (Atkinson and Impacts associated with Burrows of loricariid catfishes Taylor 1991). Members of the ma- burrows are mentioned briefly in other lit- rine family Malacanthidae are es- erature that was reviewed. For ex- pecially renowned for burrowing. To date, the most detailed dis- ample, Suzuki et al. (2000, p. 802) For example, juveniles and adults cussions on the possible effects of stated that “…Hypostomus ternetzi of the tilefish Lopholatilus loricariid catfish burrows are … deposits its eggs in nests exca- chamaeleonticeps dig burrows of based on studies and observations vated in stream banks.” Lucanus various sizes and shapes in clay of introduced loricariids in (2001) included a photograph of a substrates in deep water on the sea Hawaii. In Hawaii, non-native large catfish burrow colony that he floor, presumably as refuge from Pterygoplichthys are common and reportedly shot along the main predators. The burrows of this spe- these fish have excavated thou- channel of the Orinoco River in cies average 1.6 m in diameter and sands of nesting tunnels in the Venezuela. While collecting fish 1.7 m in depth, although the larg- earthen banks of reservoirs and in an Orinoco River tributary in est may extend several meters streams. Their burrows have been Venezuela, Leo Nico discovered a deep and are thought to be quite reported as contributing to silta- colony composed of about a dozen old (>30 years), conceivably span- tion problems and bank instability burrows along the shore of a small ning several generations if succes- (Devick 1989, Yamamoto and stream (Figure 2). During a brief sively inhabited (Able et al. 1982, Tagawa 2000). Devick (1989), investigation of the site, adult Twichell et al. 1985). assessing the impact of a large Leporacanthicus were pulled from Compared to marine fishes, population of Pterygoplichthys in two of the burrows and these few freshwater fishes are known a Hawaiian reservoir (Wahiawa), specimens ultimately were pre- to excavate and maintain burrows concluded that the burrows of this served and used as type material (Atkinson and Taylor 1991). In catfish, over the long term, were for description of a new species, addition to loricariids of the sub- having a significant impact on sil- Leporacanthicus triactis family Hypostominae, there is tation. Devick noted that there (Isbrücker et al. 1992). evidence of burrowing among were probably 30,000 or more cat- lungfishes of the Class Sarcop- fish burrows dug in the reservoir Other fishes that excavate terygii (Atkinson and Taylor in 1988, which he estimated as burrows 1991) and some members of the representing some 150 tons of ad- Among fishes, active excava- family Synbranchidae–swamp eels ditional silt accumulation in the tion and maintenance of burrows (Lüling 1958; Personal Communi- reservoir bottom. Yamamoto and has been documented largely for cation, Leo G. Nico). There are Tagawa (2000) noted a number of certain marine taxa, including probably others. Admittedly, ecological effects associated with members of the families swamp eels and certain other the introduction of Hypostomus Anguillidae–freshwater eels freshwater fishes also simply bur- sp. cf. watwata into Hawaii. In (Aoyama et al. 2005); Cepolidae– row into soft substrates or loose particular, they reported the nest- bandfishes (Atkinson and Pullin soil without creating discrete tun- ing burrows of these catfish cause 1996); Congridae–conger eels nel systems. Among these fish, erosion problems and increase silt (Tyler and Smith 1992); whether a discrete burrow is loads in Hawaiian streams.

ANSRP Bulletin, Vol-09-1, March 2009 21 However, no quantitative data Harney and Puzzle Lake and in the lichthys to excavate, but also more were provided. vicinity of Lake Jessup and likely to slump or erode. Pterygoplichthys burrows in Lemon Bluff. In these areas, It is likely that the burrowing Florida rivers and canals were Loftus also saw evidence of sub- activities of these catfish exacer- found to be similar in size and stantial sloughing of banks, which bate existing erosion problems but structure to the burrows of non- he attributed to the presence of the their overall contribution to bank native Pterygoplichthys studied in many burrows. instability and rate of erosion ap- Hawaii (Devick 1988, 1989). There are also unpublished re- pears to vary among sites. For ex- While Devick’s research in Ha- ports of Pterygoplichthys burrows ample, burrow sites examined in waii focused on inhabitants of an in Florida lakes. Moreover, al- the St. Lucie Canal were on or impounded lake, the large number though surveys were conducted in near the base of steep banks within of burrows found demonstrated relatively rural areas, the presence or just above existing rip-rap re- the potential amount of benthic of nesting Pterygoplichthys near vetment. Although the burrows habitat that these catfish can mod- human dwellings indicates that probably were contributing to ify. Whether densities of Ptery- these fish are not readily disturbed bank instability above the rip-rap goplichthys in Florida have by human activity. This behavioral of this canal, their contribution achieved the levels experienced in plasticity in selection of sites for almost certainly was low relative Mexico or Hawaii is uncertain, burrowing indicates that few to erosion caused by wave action, although incredibly high numbers freshwater habitats can be ex- in particular, the incredibly force- of Pterygoplichthys have been ob- pected to be immune from effects ful waves that strike the shore served in some Florida rivers and associated with their burrows. Ac- whenever high-speed boats and springs. At very high densities, the cording to Duan (2005), the rate of yachts pass (a common event). number of burrows could signifi- bank erosion is a function of the Pterygoplichthys burrow colonies cantly contribute to erosion of hydraulic forces, bank geometry, were discovered on outer bends of banks and modification of benthic bank material cohesion, and fre- river meanders associated with habitats. quency of bank failure. In re- small boat docks. The co- Survey results also indicate sponse to a query about the possi- occurrence may simply be due to that Pterygoplichthys are rela- ble association between catfish catfish and humans using similar tively flexible in their choice of burrows and bank erosion, the hy- criteria to select sites. For catfish sites for burrow construction, drological engineer Jennifer Duan it is the relatively steep, exposed spawning, and nesting. Habitats (personal communication) stated bank, and relatively firm soil of with burrows include small and that the burrows will make banks outer bends. For humans it is the large natural rivers and canals. Al- more unstable, will facilitate bank higher ground, which is less prone though the largest natural rivers in erosion, and then make rivers to flooding, and deep water. Prop- the survey were only moderate in more meandering. erty owners living on the river size, the St. Johns River, the larg- Based on the present field as- near colonized banks and some est river in Florida, has a substan- sessment, Pterygoplichthys boaters will likely be aware of tial Pterygoplichthys population. generally excavate their burrows Pterygoplichthys activity. During low water conditions in in shoreline habitats of rivers and In addition to Pterygoplichthys 2007, large numbers of burrows canals already prone to erosion and various other fishes, a diverse were observed in exposed banks (e.g., outer bends of meandering array of aquatic and many terres- of the river’s main channel. More rivers, steep banks often com- trial animals commonly excavate recently, Dr. William Loftus (per- posed of sandy-clay-loams with burrows. Negative effects associ- sonal communication) boated on sparse vegetation cover). They ated with the burrows and burrow- the upper St. Johns River in early typically select relatively steep ing activities of these animals 2009 during low water and ob- banks with soils friable enough to vary, typically depending on the served thousands of exposed dig into, yet stable enough to not local setting (i.e., vulnerability of Pterygoplichthys burrows along collapse easily. Such bank condi- the site), the abundance of the bur- the banks in areas between Lake tions make it easier for Pterygop- rowing species, and the number,

22 ANSRP Bulletin, Vol-09-1, March 2009 size, and configuration of the bur- roots are more armored against stream banks of the Bay’s tributar- rows. Negative effects may be erosion. ies (Rudnick et al. 2005). economic or ecological, although In addition to Pterygoplicthys In their recent assessment of neither is mutually exclusive (e.g., and Hypostomus, a number of crab burrow impacts in intertidal Williams and Corrigan 1994, other non-native species intro- portions of tributaries in South Gabet et al. 2003). duced into North America exca- San Francisco Bay, Rudnick et al. In general, most impacts asso- vate burrows and have been impli- (2005) reported that Chinese mit- ciated with burrows are attributed cated in causing environmental ten crabs removed an estimated 1 to their possible contribution to harm to shoreline habitats due to to 6 percent of sediment per 0.5 erosion and bank instability and, their burrowing activities. Exam- m3 of stream bank through bur- related to this, damage caused to ples include the Chinese mitten rowing activities over the period existing man-made structures crab (Eriocheir sinensis) in the of study (2000–2002). They noted (e.g., dams, retention walls, and San Francisco Bay-San Joaquin localized bank slumping, particu- foundations) because of undermin- Delta of California (Rudnick et al. larly in spring following rain ing. Animals that burrow in or 2000, 2005), the Austral-Asian events. According to the research- near waterways may be particu- isopod (Sphaeroma quoyanum) in ers, sediment loss from burrowing larly problematic because their salt marshes of San Diego Bay and activities may be substantial in the activities may increase bank insta- San Francisco Bay (Talley et al. intertidal tributaries where the bility, erosion, and siltation. In the 2001), and the green iguana crabs occur. Sediment loss was vicinity of earthen dams, burrows (Iguana iguana) in southern Flor- reported to be influenced by mul- may dramatically alter hydraulics ida (Kern 2004, Ferriter et al. tiple factors including crab popu- or flownet within the embank- 2008). lation abundance, connectivity of ment, thereby damaging and lead- The burrowing activities of the burrow systems, and sediment ing to possible failure of the dam non-native Chinese mitten crabs, composition. structure (Federal Emergency especially where the species is The burrowing isopod Management Agency (FEMA) abundant and burrows very dense, Sphaeroma quoyanum from 2005). have been linked to bank weaken- Australia-New Zealand was first According to Meadows and ing, erosion, loss of bank vegeta- reported in California in the late Meadows (1991), the burrows of tion, and bank collapse (Herborg 1800s. Wasson et al. (2001) stated animals can alter the water con- et al. 2003, Rudnick et al. 2000, that the burrows of this isopod rid- tent, permeability, shear strength, 2005, and citations therein). Her- dled virtually every bank exam- and other geotechnical properties borg et al. (2003) analyzed the his- ined in one estuary, which they of the sediment matrix. Greater tory of these introduced crabs in noted was perhaps exacerbating stream flows increase the risk of Europe and noted that their bur- already high rates of tidal erosion. bank failure, and undercutting row-digging habit can cause seri- Talley et al. (2001) examined tends to exacerbate the situation ous river bank erosion, usually habitat alteration by this non- (Wynn 2004). Based on these rela- observed in tidally-influenced ar- native isopod in California salt tionships, the occurrence of Ptery- eas or other stretches of rivers marshes. In these habitats, the iso- goplichthys burrows along the with fluctuations in water level. pod typically selected peat and outer bends of rivers where the Burrows are made in river banks mud walls of tidal creek and force of the current is often great- with steep gradients, sites having marsh edge banks for their bur- est may very well further increase soil with the necessary structural rows. Using enclosure experi- the probability of bank failure. In strength to allow burrowing. The ments, the investigators were able contrast, banks with woody and appearance of this non-native in to demonstrate that isopod activi- herbaceous root mats significantly California was a concern partly ties enhanced sediment loss from increase bank slope stability over because of their potential impact banks and estimated that some bare conditions (Wynn 2004), to the integrity of the extensive losses exceeded 100 cm of marsh consequently, sites where Ptery- levee system in the San Francisco edge per year. Talley et al. con- goplichthys burrow among tree Bay region as well as the natural cluded that the effects of habitat

ANSRP Bulletin, Vol-09-1, March 2009 23 alteration by this invading species natural systems is a complex (Figures 24 and 25). Their envi- are likely to increase in severity in undertaking. Cause-effect rela- ronmental threat is a combination the coastal zone as these ecosys- tionships are difficult to establish of distinctive life history attrib- tems become degraded. According because of many interacting biotic utes, especially feeding and repro- to Talley et al. (2001), others had and abiotic variables. Non-native ductive behaviors, coupled with noted that the intensive burrowing Pterygoplichthys populations in their large size and high popula- activities of this species weakened Florida and other regions are tion densities (Fuller et al. 1999, mud and clay banks of salt marsh highly successful invaders and Hoover et al. 2004). edges, thus making them more considered a threat to native Increasing numbers and distri- susceptible to erosion by wave aquatic communities and habitats bution of Pterygoplichthys have action or stream flow. However, the researchers stated that their study was the first to quantify impacts caused by the isopod’s burrowing. The green iguana (Iguana iguana) is another non-native in North America that digs burrows. Ferriter et al. (2008) reported that large numbers of non-native iguana burrows can be observed in the banks of many canals and lev- ees in and around the Greater Everglades. They noted that these burrows present a maintenance liability, leading to bank instability and bank erosion. Ferriter et al. stated that further evaluations are Figure 24. Pterygoplichthys have become abundant in many Florida waterways needed to fully understand the im- but their impacts are difficult to quantify, especially in complex natural systems. In February 2007 a large number of these non-native catfish were observed pact of burrows on bank integrity massed in Alexander Spring, Florida. (Photograph by Brian MacGregor) and maintenance costs. However, the researchers concluded that even moderate densities of green iguanas have some impact on bank stability. In a separate analysis, Kern (2004) reported that the burrows of non-native populations in south Florida undermine seawalls, sidewalks, and foundations. Burrows next to seawalls allow erosion and eventual collapse of the structure. The environmental effects caused by introduced loricariid catfishes remain inadequately documented and generally little understood. The substantial gap in Figure 25. Non-native Pterygoplichthys gathering around an adult female man- atee and her yearling calf at Blue Springs, Volusia County, Florida. The catfish knowledge is due to a variety of often settle on manatees to possibly rest or graze on algae that commonly grows factors. Analysis of impacts in on their backs. (Photograph by James P. Reid, U.S. Geological Survey)

24 ANSRP Bulletin, Vol-09-1, March 2009 undoubtedly been accompanied by Pterygoplichthys in Florida and to rows were mostly aggregated into an increase in the number and dis- provide a preliminary assessment colonies. Among the six water- tribution of Pterygoplichthys bur- of shoreline conditions (e.g., bank ways surveyed, burrows were dis- rows and burrow colonies. Future stability and erosion). Waterways tributed among 18 sites, with the research into the durability of bur- surveyed for catfish burrows in- number of burrows per site rang- rows and colonies through fluctu- cluded parts of six rivers and ca- ing from 1 to 16 (mean = 6.6). The ating water conditions should bet- nals: St. Lucie Canal, Okeechobee 2-km section of the Peace River ter inform about erosion impacts. Rim Canal, Peace River, Withla- that was sampled had the highest Understanding Pterygoplichthys coochee River, Alafia River, and densities of burrow colonies (2.5 nesting behavior and burrow fidel- Oklawaha River. per km) and burrows (20.5 per ity would also give some indica- Field surveys were conducted km). In natural rivers, burrow tions of burrow maintenance and during spring-early summer 2006 colonies were much more evident persistence. when water levels in peninsular in upstream portions of natural Florida were low and the likeli- drainages where there were hood of detecting burrows, espe- steeper banks and greater fluctua- Summary cially those exposed by low water, tions in water levels. In these riv- is greatest. During the study pe- ers, colonies were found along the Non-native populations of the riod, approximately 56 km of wa- outer bends of channels, although Neotropical family Loricariidae, terway were surveyed. Burrows the geometry of bends selected the suckermouth armored catfishes were detected in five of the six varied from slight meanders to (also referred to as loricariid cat- waterways surveyed. The only ex- sharp. In canals, burrows were fishes), have been introduced and ception was the Lake Okeechobee found along straight sections become established in many tropi- Rim Canal. That canal had many where much of the bank was ex- cal and subtropical regions of the exposed cavities along the upper posed and steep. world. In Florida, members of the edge of banks; however, because The horizontal extent (i.e., loricariid genus Pterygoplichthys of the extreme degradation of alignment parallel to shoreline) of are now common in most drain- these holes, it could not be deter- colonies varied widely, ranging ages in the central and southern mined that these undercuts had from about one or a few meters for parts of the peninsula. In certain been created by Pterygoplichthys. small colonies, to well over 15 m rivers, canals, and lakes, these In total, the presence of 118 for colonies composed of many fishes are abundant. burrows considered to have been burrows. In contrast, the vertical Breeding adult Pterygoplich- excavated by Pterygoplichthys layouts of most colonies were thys excavate and maintain bur- were documented. Of the burrows within a 1-m stratum of shoreline. rows in shoreline soil. These bur- detected, 85 (72 percent) had en- Complete measurements were rows are used mostly as spawning trances that were exposed above taken for 63 burrows and 58 of and nesting sites. The burrows are the water edge, either entirely or these were considered to be in suf- thought to cause or exacerbate partially (>50 percent of burrow ficient condition to be included in bankline erosion in canals and riv- height). Some sites included a statistical analyses. Most burrows ers. However, there is little pub- combination of both submerged (61 of 63 burrows examined) were lished information on the burrows and exposed burrows. All detected rather simple structures, consisting of loricariid catfishes and no quan- burrows were located along the of a single opening and a rela- titative data are available to river and canal banks. No burrows tively straight tunnel without adequately evaluate any associa- were observed in the beds of wa- marked bends or bifurcations. tion between presence and abun- terways, although some waterways Burrow tunnels ranged from 20 to dance of burrows and increased were too deep and turbid to detect 130 cm (mean = 77 cm) in length, erosion. bottom burrows. and the dimensions of the entrance The purpose of the present Findings indicated that bur- ranged from 11 to 45 cm (mean = study was to provide baseline in- rows were not distributed evenly 21 cm) in width, and 7 to 27 cm formation on the burrows of within or among waterways. Bur- (mean = 14 cm) in height.

ANSRP Bulletin, Vol-09-1, March 2009 25 Variation in both tunnel length near the base of steep banks within canals were similar in size and and volume was likely related to or just above existing rip-rap re- structure to burrows associated burrow age and condition. The vetment. Although the burrows with introduced populations in largest and longest burrows were probably were contributing to Hawaii (Devick 1988, 1989). active burrows, submerged and bank instability above the rip-rap While Devick’s research in Ha- occupied by an adult Pterygop- of this canal, their contribution waii focused on an impounded lichthys. almost certainly was low relative lake situation, the large number of Habitats with burrow colonies to erosion caused by wave action, burrows found there demonstrated were fairly diverse, evidence that in particular the incredibly force- the potential amount of benthic Pterygoplichthys are relatively ful waves that strike the shore habitat that these catfish can mod- flexible in their choice of sites for when high-speed boats and yachts ify. It is uncertain whether densi- burrow construction, spawning, pass. Boat traffic on the St. Lucie ties of loricariid catfishes in Flor- and nesting. For example, the Canal was high during the survey ida have reached the levels height, cross-sectional shape, and and may act synergistically with experienced in Mexico or Hawaii general slope of river and canal burrows to increase erosion in because of a shortage of field sur- banks with colonies were also di- some sites. veys. At very high densities, the verse. Soil was sampled at eight Based on burrow volumes and number of burrows could signifi- colonies and subsequent analysis numbers of burrows per site, cantly contribute to erosion of of particle sizes indicated that soil Pterygoplichthys were estimated banks and modification of benthic composition was a mixture of fine to remove 1 to 4 percent of sedi- habitats. and very fine sands and silts-clay, ment per rectangular (1 m deep) with the most common soil type volume of bank through their bur- being sandy-clay-loams. rowing activities. However, esti- Acknowledgments In terms of bank stability and mates may be low since many of erosion, general observations on the burrows measured in the study For assistance in the field, the the nest burrow sites indicate that were abandoned and relatively authors thank Linda S. Nico and Pterygoplichthys generally exca- small (presumably because of ero- Robert J. Lewis. Assistance and vate their burrows in shoreline sion). Abandoned and exposed advice provided by Jan Hoover is habitats of rivers and canals al- burrows were about half the vol- appreciated. A number of other ready prone to erosion (e.g., outer ume of the few active burrows en- individuals provided useful infor- bends of meandering rivers, steep countered. mation. Jennifer Duan of the Uni- banks often composed of sandy- Some Pterygoplichthys burrow versity of Arizona kindly re- clay-loams with sparse vegetation colonies on outer bends of river sponded to questions concerning cover). They typically select rela- meanders were associated with bank stability. Employees of the tively steep portions of banks with small boat docks. The co- South Florida Water Management soils friable enough to dig into, yet occurrence may simply be due to District, including Eduardo Patino, stable enough to not collapse eas- catfish and humans using similar Sara Hammermeister, and Ricardo ily. Such bank conditions make it criteria to select sites. For catfish Solis, responded to our requests easier for Pterygoplichthys to ex- it is the relatively steep, exposed for burrow sightings. Jon Arm- cavate, but also more likely to bank, and relatively firm soil of bruster suggested identifications slump or erode. outer bends. For humans it is the based on fish specimens and It is likely that the burrowing higher ground, less prone to flood- specimen photographs. Several activities of these catfish exacer- ing, and deep water. In any case, other individuals kindly shared bate existing erosion problems but property owners living along information on the location of their overall contribution to bank waterways near colonized banks burrows. For their assistance, the instability and rate of erosion ap- and some boaters will likely be authors thank William Loftus, peared to vary among sites. For aware of Pterygoplichthys activity. David and Jared Brimer, and Cap- example, burrow sites examined in We found that Pterygoplich- tain Mike Tracy. William Bussing the St. Lucie Canal were on or thys burrows in Florida rivers and responded to questions concerning

26 ANSRP Bulletin, Vol-09-1, March 2009 loricariids in Central America. Burgess, W. E. 1989. An atlas of fresh- Vi Catrow and others from the Literature Cited water and marine catfishes—a pre-

U.S. Geological Survey’s Leetown liminary survey of the Siluriformes. Able, K. W., C. G. Grimes, R. A. Cooper, Neptune City, NJ: TFH Publications. Science Library helped in search- and J. R. Uzmann. 1982. Burrow con- Bussing, W. A. 2002. Freshwater fishes ing the literature. The authors struction and behavior of tilefish, of Costa Rica. San José, Costa Rica: thank James P. Reid and Brian Lopholatilus chamaeleonticeps, in Editorial de la Universidad de Costa MacGregor for granting permis- Hudson Submarine Canyon. Envi- Rica. sion to use their photographs. Jan ronmental Biology of Fishes 7:199– Carter, G. S., and L.C. Beadle. 1931. The 205. fauna of the swamps of the Para- Hoover, Gary L. Mahon, Stephen Aoyama, J., A. Shinoda, S. Sasai, M. J. guayan Chaco in relation to its envi- Walsh, and Lisa Jelks are also Miller, and K. Tsukamoto. 2005. First ronment. II. Respiratory adaptations thanked for reviewing drafts of observations of the burrows of An- in the fishes. Journal of the Linnean this manuscript. This study was guilla japonica. Journal of Fish Biol- Society of London (Zoology) 37:327– funded by the U.S. Army Corps of ogy 67:1534–1543. 368. Armbruster, J. W., and L. M. Page. 2006. Chavez, J. M., R. M. de la Paz, S. K. Engineers, Aquatic Nuisance Redescription of Pterygoplichthys Manohar, R. C. Pagulayan, R. C. Species Research Program. Per- punctatus and description of a new Pagulayan, and J. R. Carandang. mission to publish this document species. Neotropical Ichthyology 2006. New Philippine record of South was provided by the Chief of En- 4:401–409. American sailfin catfishes (Pisces: gineers. Use of any trade, product, Atkinson, R. J. A., and R. S. V. Pullin. Loricariidae). Zootaxa 1109:57–68. 1996. Observations on the burrows Clarke, K. R., and R. M. Warwick. 2001. or firm names is for descriptive and burrowing behaviour of the red Change in marine communities: an purposes only and does not band-fish, Cepola rubescens L. Ma- approach to statistical analysis and imply endorsement by the rine Ecology 17:23–40. interpretation, 2nd edition. Plymouth, U.S. government. Atkinson, R. J. A., and A. C. Taylor. United Kingdom: PRIMER-E. 1991. Burrows and burrowing behav- Clark, E., S. N. Kogge, D. R. Nelson, T. iour of fish. In The environmental im- K. Alburn, and J. F. Pohle. 2006. Bur- pact of burrowing animals and ani- row distribution and diel behavior, of Points of Contact mal burrows, ed. P. S. Meadows and the coral reef fish Pholidichthys leu- A. Meadows, 133–155. Oxford, Eng- cotaenia (Pholidichthyidae). Aqua, For additional information, land: Clarendon Press. International Journal of Ichthyology please contact Dr. Jan J. Azevedo, P. 1938. O cuscudo dos açudes 12:45–82. Colin, P. L. 1973. Burrowing behavior of Hoover (601-634-3996; nordestinos, “Plecostomus plecostomus.” Arquivos do Instituto Biologico the yellowhead jawfish, Opistog- [email protected]) or São Paulo 9(20):211–224. nathus aurifrons. Copeia 1973:84–90. the Manager of the Aquatic Nui- Berra, T. M. 2001. Freshwater fish dis- Couper, P. R. 2004. Space and time in sance Species Research Program, tribution. New York-London: Aca- river bank erosion research: A review. Dr. Linda Nelson (601-634-2656; demic Press. Area 36:387–403. Covain, R., and S. Fisch-Muller. 2007. [email protected]. Birindelli, J. L. O., A. M. Zanata, and F. C. T. Lima. 2007. Hypostomus chry- The genera of the Neotropical ar- This bulletin should be cited as sostiktos, a new species of armored mored catfish subfamily Loricariinae follows: catfish (Siluriformes: Loricariidae) (Siluriformes: Loricariidae): A practi- from rio Paraguaçu, Bahia State, Bra- cal key and synopsis. Zootaxa Nico, L. G., H. L. Jelks, and zil. Neotropical Ichthyology 5:271– 1462:1–40. T. Tuten. 2009. Non-Native 278. Delariva, R. L., and A. A. Agostinho. suckermouth armored catfishes Breder, C. M., Jr., and D. E. Rosen. 1966. 2001. Relationship between morphol- in Florida: Description of nest Modes of reproduction in fishes. Nep- ogy and diets of six neotropical lori- burrows and burrow colonies tune City, NJ: TFH Publications. cariids. Journal of Fish Biology Bunkley-Williams, L., E. H. Williams, 58:832–847. with assessment of shoreline Jr., C. G. Lilistrom, I. Corujo-Flores, Devick, W. S. 1988. Disturbances and conditions. ANSRP Bulletin, A. J. Zerbi, C. Aliaume, and T. N. fluctuations in the Wahiawa Reser- Vol-09-01. Vicksburg, MS: Churchill. 1994. The South American voir ecosystem. Project F-14-R-12, U.S. Army Engineer Research sailfin catfish Liposarcus multiradia- Job 4, Study I. Nomolulu, HI: Divi- and Development Center. tus (Hancock), a new exotic estab- sion of Aquatic Resources, Hawaii lished in Puerto Rican fresh waters. Department of Land and Natural Caribbean Journal of Science 1– Resources. 2:90–94.

ANSRP Bulletin, Vol-09-1, March 2009 27 Devick, W. S. 1989. Disturbances and Gonzalez, T. T., M. Katoh, and A. Ishi- University of Florida. Available: fluctuations in the Wahiawa Reser- matsu. 2008. Intertidal burrows of the http://edis.ifas.ufl.edu/pdffiles/IN/IN5 voir ecosystem. Project F-14-R-13, air-breathing eel goby, Odontambly- 2800.pdf (accessed 19 April 2007). Job 4, Study I. Honolulu, HI: Divi- opus lacepedii (Gobiidae: Amblyopi- Kottelat, M., A. J. Whitten, S. N. Karti- sion of Aquatic Resources, Hawaii nae) Ichthyological Research 55:303– kasari, and S. Wirjoatmodjo. 1993. Department of Land and Natural Re- 306. Freshwater fishes of Western Indone- sources, Honolulu. 30 pp. Grier, H. 1980. Plecostomus. Freshwater sia and Sulawesi. Sri Lanka: Periplus Duan, J. G. 2005. Analytical approach to and Marine Aquarium 3(8):23–26, Editions, Wildlife Heritage Trust of calculate rate of bank erosion. Jour- 85. Sri Lanka. nal of Hydraulic Engineering Herborg, L.-M., S. P. Rushton, A. S. Lawler, D. M. 1986. River bank erosion 131:980–990. Clare, and M. G. Bentley. 2003. and the influence of frost: a statistical Eric, G., E. Moodie, and M. Power. 1982. Spread of the Chinese mitten crab examination. Transactions of the In- The reproductive biology of an ar- (Eriocheir sinensis H. Milne Ed- stitute of British Geographers, New moured catfish, Loricaria uracantha, wards) in Continental Europe: Analy- Series 11:227–242. from Central America. Environmental sis of a historical data set. Hydrobi- Levin, B. A., P. H. Phuong, and D. S. Biology of Fishes 7:143–148. ologia 503:21–28. Pavlov. 2008. Discovery of the Ama- Federal Emergency Management Agency Hoover, J. J., K. J. Killgore, and A. F. zon sailfin catfish Pterygoplichthys (FEMA). 2005. Technical manual for Cofrancesco. 2004. Suckermouth cat- pardalis (Castelnau, 1855) (Teleostei: dam owners: impacts of animals on fishes: Threats to aquatic ecosystems Loricariidae) in Vietnam. Journal of earthen dams. Federal Emergency of the United States? Aquatic Nui- Applied Ichthyology 24:715–717. Management Agency, US Department sance Species Research Bulletin Liang, S. H., H. P. Wu, and B. S. Sheih. of Homeland Security. FEMA 4(1):1–9. 2005. Size structure, reproductive 473/September 2005. Available: Isbrücker, I. J., H. Nijssen, and L. G. phenology, and sex ratio of an exotic www.fema.gov/plan/prevent/damfailu Nico. 1992. Ein neuer Rüssel- armored catfish (Liposarcus multira- re/pdf/fema-534.pdf (Oct 2006). zahnwels aus oberen Orinoco- diatus) in the Kaoping River of Ferriter, A., B. Doren, D. Thayer, B. Zuflüssen in Venezuela und southern Taiwan. Zoological Studies Miller, T. Pernas, S. Hardin, J. Lane, Kolumbien: Leporacanthicus triactis 44(2):157–168. M. Kobza, D. Schmitz, M. Bodle, L. n. sp. (Pisces, Siluriformes, Loricarii- Lim, K. K. P., and P. K. L. Ng. 1990. A Toth, L. Rodgers, P. Pratt, S. Snow, dae). Die Aquarien- und Terrarien- guide to the freshwater fishes of Sin- and C. Goodyear. 2008. The status of zeitschrift 46(1):30–34. gapore. Singapore: Singapore Science nonindigenous species in the South Ishimatsu, A., Y. Hishida, T. Takita, T. Centre. Florida environment. Chapter 9 in Kanda, S. Oikawa, T. Takeda, and K. Lucanus, O. 2001. Fish from the Upper 2008 South Florida Environmental H. Khoo. 1998. Mudskippers store air Orinoco. Tropical Fish Hobbyist Report. Available: in their burrows. Nature 391:237– 49(11) (July):62–64, 66, 68–70. https://my.sfwmd.gov/pls/portal/docs/ 238. Lüling, K. H. 1958. Über die Atmung, PAGE/PG_GRP_SFWMD_SFER/PO Itani, G., and T. Uchino. 2003. Burrow amphibishche Lebensweise und Futte- RTLET_SFER/TAB2236041/VOLUM morphology of the goby Taenioides raufnahme von Synbranchus marmo- E1/chapters/v1_ch_9.pdf (Sept 2008). cirratus. Journal of the Marine Bio- ratus (Pisces, Synbranchidae). Bonner Fuller, P. L., L. G. Nico, and J. D. Wil- logical Association of the United Zoologische Beiträge 9(1):68–94. liams. 1999. Nonindigenous fishes in- Kingdom 83:881–882. Meadows, P. S., and A. Meadows (edi- troduced into inland waters of the Jones, A. D. 2008. Suckermouth catfish tors). 1991. The environmental im- United States. American Fisheries (Pterygoplichthys pardalis). Aliens of pact of burrowing animals and animal Society Special Publication 27. Be- Xamayca 1(4):1. Available: burrows. In Symposia of the Zoologi- thesda, MD. www.jamaicachm.org.jm/Article/PDF cal Society of London Number 63. Gabet, E. J., O. J. Reichman, and E. W. /October2008.pdf Oxford: Clarendon Press. Seabloom. 2003. The effects of bio- Jones, R. S., E. J. Gutherz, W. R. Nelson, Mendoza, R., S. Contreras, C. Ramirez, turbation on soil processes and sedi- and G. C. Matlock. 1989. Burrow and P. Koleff. 2006. Invasion of ple- ment transport. Annual Review of utilization by yellowedge grouper, cos in Infiernillo Dam, socio- Earth and Planetary Sciences Epinephelus flavolimbatus, in the economic status. Unpublished report. 31:249–273. northwestern Gulf of Mexico. Envi- Nakabo, T. (editor). 2002. Fishes of Ja- Garcia-Pinto, L., G. Quiñones-Gonzalez, ronmental Biology of Fishes 26:277– pan with pictorial keys to the species, and G. Friso. 1984. Biología repro- 284. English edition, II. Tokyo, Japan: To- ductiva de Hypostomus watwata Kern, W. H., Jr. 2004. Dealing with kai University Press. (Osteichthyes-Loricariidae), arma- iguanas in the South Florida land- Nash, R. D. M. 1980. Laboratory obser- dillo pintado del Lago de Maracaibo, scape. Fact Sheet ENY-714, Ento- vations on the burrowing of the snake Venezuela. Centro de Aprendizaje mology and Nematology Department, blenny, Lumpenus lampretaeformis Agropecuario "Don Bosco" Florida Cooperative Extension (Walbaum), in soft sediment. Journal Carrasquero Estado Zulia - Vene- Service, Institute of Food and of Fish Biology 16:639–648. zuela - Boletín Técnico 3:1–21. Agricultural Sciences (IFAS),

28 ANSRP Bulletin, Vol-09-1, March 2009 Nelson, J. S. 2006. Fishes of the world, Rudnick, D. A., V. Chan, and V. H. Suzuki, H. I., A. A. Agostinho, and K. O. 4th edition. New York: John Wiley Resh. 2005. Morphology and impacts Winemiller. 2000. Relationship be- and Sons. of the burrows of the Chinese mitten tween oocyte morphology and repro- Nico, L. G. 2005. Changes in the fish crab, Eriocheir sinensis H. Milne ductive strategy in loricariid catfishes fauna of the Kissimmee River basin, Edwards (Decapoda, Grapsoidea), in of the Paraná River, Brazil. Journal of peninsular Florida: Non-native addi- South San Francisco Bay, California, Fish Biology 56:791–807. tions. In Historical changes in large U.S.A. Crustaceana 78:787–807. Talley, T. S., J. A. Crooks, and L. A. river fish assemblages of the Ameri- Rudnick, D. A., K. M. Halat, and V. H. Levin. 2001. Habitat utilization and cas, ed. J. N. Rinne, R. M. Hughes Resh. 2000. Distribution, ecology and alteration by the burrowing isopod, and B. Calamusso, 523–556. Be- potential impacts of the Chinese mit- Sphaeroma quoyanum, in California thesda, MD: American Fisheries So- ten crab (Eriocheir sinensis) in San salt marshes. Marine Biology 138: ciety Symposium 45. Francisco Bay. Technical Completion 561–573. Nico, L. G., and R. T. Martin. 2001. The Report, Project Number: UCAL- Twichell, D. C., C. B. Grimes, R. S. South American suckermouth ar- WRC-W-881. Berkley, CA: Univer- Jones, and K. W. Able. 1985. The mored catfish Pterygoplichthys anis- sity of California, Department of En- role of erosion by fish in shaping to- itsi (Pisces: Loricariidae) in Texas, vironmental Science, Policy and pography around Hudson Submarine with comments on foreign fish intro- Management. Available: Canyon. Journal of Sedimentary Pe- ductions in the American Southwest. http://www.lib.berkeley.edu/WRCA/W trology 55:712–719. Southwestern Naturalist 46:98–104. RC/pdfs/contribution_206.pdf Tyler, J. C., and C. L. Smith. 1992. Sys- Nico, L. G., and D. C. Taphorn. 1994. (Oct 2006). tematic significance of the burrow Mercury in fish from gold mining re- Sabaj, M. H., J. W. Armbruster, and L. form of seven species of garden eels gions in the upper Cuyuni River sys- M. Page. 1999. Spawning in Ancis- (Congridae, Heterocongrinae). tem, Venezuela. Fresenius Environ- trus with comments on the evolution American Museum Novitates 3037:1– mental Bulletin 3:287–292. of snout tentacles as a novel repro- 13. Ott, R. A. 2000. Factors affecting stream ductive strategy: larval mimicry. Ich- Vidthayanon, C. 2005. Aquatic alien spe- bank and river bank stability, with thyological Exploration of Fresh- cies in Thailand (Part1): Biodiversity. emphasis on vegetation influences: waters 10:217–229. In International mechanisms for the An annotated bibliography. Report Sabaj, M. H., and R. A. Englund. 1999. control and responsible use of alien compiled for the Region III Forest Preliminary identification and current species in aquatic ecosystems, Report Practices Riparian Management distributions of two suckermouth of an Ad Hoc Expert Consultation. Committee. Tanana Chiefs Confer- armored catfishes (Loricariidae) in- Xishuangbanna, People’s Republic of ence, Inc. Forestry Program, Fair- troduced to O'ahu streams. Bishop China, 27–30 August 2003, ed. D. M. banks, Alaska. Available: Museum Occasional Papers 59:50– Bartley, R. C. Bhujel, S. Funge- http://www.dnr.state.ak.us/forestry/pd 55. Smith, P. G. Olin, and M. J. Phillips, fs/2BankStabilityfinal.pdf (Accessed Saint-Paul, U., J. Zuanon, M. A. Villa- 113–117. Rome: FAO. 2 May 2007) corta-Correa, M. Garcia, N. N. Fabre, Wakida-Kusunoki, A., R. Ruiz-Carus, Ozdilek, S. Y. 2007. Possible threat for U. Berger, and W. J. Junk. 2000. Fish and E. Amador-del-Angel. 2007. Middle East inland water: An exotic communities in central Amazonian Amazon sailfin catfish, Pterygoplich- and invasive species, Pterygoplich- white- and blackwater floodplains. thys pardalis (Castelnau, 1855) (Lori- thys disjunctivus (Weber, 1991) in Environmental Biology of Fishes cariidae), another exotic species es- Asi River, Turkey (Pisces: Loricarii- 57:235–250. tablished in southeastern Mexico. dae). E.U. Journal of Fisheries and Schaefer, S. A., and D. J. Stewart. 1993. Southwestern Naturalist 52:141–144. Aquatic Sciences (E.Ü. Su Ürünleri Systematics of the Panaque dentex Wasson, K., C. J. Zabin, L. Bedinger, M. Dergisi) 24(3-4):303–306. species group (Siluriformes: Lori- C. Diaz, and J. S. Pearse. 2001. Bio- Page, L. M., and R. H. Robins. 2006. cariidae), wood-eating armored cat- logical invasions of estuaries without Identification of sailfin catfishes fishes from tropical South America. international shipping: The impor- (Teleostei: Loricariidae) in southeast- Icthyological Exploration of Fresh- tance of intraregional transport. Bio- ern Asia. The Raffles Bulletin of Zo- water 4:309–342. logical Conservation 102:143–153. ology 54:455–457. Serov, D. 2004. Harnischwelse in Williams, D. E., and R. M. Corrigan. Randall, J. E., and J. L. Earle. 2006. Am- Südostasien. Die Aquarien- und Ter- 1994. Chipmunks. In Prevention and blyeleotris neumanni, a new species rarienzeitschrift (DATZ) 57(2):18-19. control of wildlife damage, ed. S. E. of shrimp goby from New Britain. (In German.) Hygnstrom, R. M. Timm, and G. E. Aqua Journal of Ichthyology and Shafland, P. L., K. B. Gestring, and M. S. Larson, B13–B16. Lincoln, NB: Uni- Aquatic Biology 11(1):19–24. Stanford. 2008. Florida's exotic versity of Nebraska. Available: Reis, R. R., S. O. Kullander, and C. J. freshwater fishes–2007. Florida Sci- http://icwdm.org/handbook/allPDF/R Ferraris, Jr. (editors). 2003. Check list entist 71:220–245. O_B13.PDF (Accessed 11 October of freshwater fishes of South and Cen- 2006) tral America. Porto Alegre, Brazil: EDIPUCRS.

ANSRP Bulletin, Vol-09-1, March 2009 29 Wynn, T. M. 2004. The effects of vegetation on stream bank erosion. Unpub- About the Authors: lished PhD diss, Virginia Polytechnic Institute and State University, Blacksburg. Available: Leo G. Nico is a research fishery biologist http://scholar.lib.vt.edu/theses/ with the Florida Integrated Science Center of available/etd-05282004- the U.S. Geological Survey in Gainesville, FL. 115640/unrestricted/Chapters1-2.pdf He holds B.S. and M.S. degrees in biology (Accessed 30 April 2007) from Southern Illinois University-Edwardsville Yamamoto, M. N., and A. W. Tagawa. and a Ph.D. in zoology from the University of 2000. Hawaii’s native and exotic Florida. Dr. Nico’s current research interests freshwater animals. Honolulu, HI: include the distribution, ecology, natural his- Mutual Publishing. tory, and ecological effects of nonindigenous Yossa, M. I., and C. A. R. M. Araujo- fishes. His M.S. and Ph.D. field research was Lima. 1998. Detritivory in two Ama- zonian fish species. Journal of Fish conducted in South America and involved Biology 52:1141–1153. studies on the ecology and natural history of annual fishes and piranhas. Contact information and curriculum vitae are available at: http://fl.biology.usgs.gov/All_Staff/nico.html

Howard L. Jelks is a research fishery biologist with the Florida Integrated Science Ceter of the U.S. Geological Survey in Gainesville, FL. He holds a B.S. degree in biological sci-

ences from The Florida State University and an M.S. in wildlife and range sciences from the University of Florida. His research interests and expertise are diverse and have included investigations on wetland plants, aquatic invertebrates, imperiled native fish,

nonindigenous fish, coral reef fish, and wad- ing birds. His contact information and curriculum vitae are available at: http://fl.biology.usgs.gov/All_Staff/HLJcv-

bio3-07.pdf

Travis Tuten is a biologist with the Florida Fish and Wildlife Conservation Commission in Gainesville, FL. He holds a B.S. degree in wildlife ecology and conservation and an M.S. in fisheries and aquatic sciences from the University of Florida. His expertise is in freshwater fisheries. Professional experience includes field studies on native and nonindi-

genous fishes of lakes and rivers of Florida.

His M.S. research focused on the diet and growth of black crappie. Contact: 352-955- 3220, [email protected]

The contents of this bulletin are not to be used for advertising, publication, or promotional purposes nor are they to be published without proper credit. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products.

30 ANSRP Bulletin, Vol-09-1, March 2009