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Home , Goatfish, Mullus, Striped red mullet

Site Fidelity, Home Ranges and Homing in Mediterranean Red Striped , surmuletus

Maggie McFarland

Bio159 - Marine Ecology Field Quarter, University of California, Santa Cruz

ABSTRACT

Site fidelity, home range and homing were determined in goatfish, Mullus surmuletus using bead tags, visual surveys and translocation on SCUBA in Calvi, Corsica. Site fidelity was supported by evidence of home ranges that averaged (70.56m2 ± S.D. 56.36m2 ). Homing was supported by the return of an established home range individual, who was transported twice and returned twice, despite the calculated 99.99% probability of the individual not being found within the defined home range area. Giving insight into the movement patterns of red striped goatfish, better protection against high exploitation by commercial fisheries can be pursued.

INTRODUCTION such as habitat affiliations, interspecies connections and social structures (Freiwald 2009). Site fidelity is an ’s choice to be consistently faithful to a particular location or site to increase its The red striped goatfish, Mullus surmuletus, is a fitness. It is recognizable by the presence of a home species that exhibits unique behavior blahablah. It can range. A home range is only defined by the particular be recognized by the cohorts of feeding creating movement patterns of the individual (Freiwald 2012). a sediment and detritus cloud while foraging through The shapes and areas of home ranges are often sand with its barbels, a structure blahblah. While M. influenced by the abundance or location of resources, surmuletus global distribution has been determined the habitat structure, the presence of competition, and (Bauchot 1987, Labropoulou et al. 1997), the the size of the moving individual. As the site fidelity is movement patterns of M. surmuletus, have not been the behavior of choice and home ranges are the investigated and are currently unknown. manifestations of that choice, the ability of an animal The goal of my study is to further the understand to return that specific “home” or goal location is called movement patterns and behaviors of M. surmuletus. homing (Bingman 2004). More specifically, to determine the presence of site Two of the frequently studied species in homing fidelity, home ranges and homing within red striped research include spawning coho salmon (Cooper et. al. goatfish. I hypothesized that: 1976) and homing pigeons (Wiltschko 1978). The (I) Goatfish fidelity can be supported by the mapping energy expenditures of returning, at times from great of home ranges of tagged goatfish. distances, to home are outweighed by the benefits (II) Following translocation outside of its home range found within the “goal” location, such as mates, border, a goatfish will return to its home range, resources or refuge. An understanding of the demonstrating homing and further supporting the movement patterns of an animal helps to prove theory of site fidelity. researchers with insight into life history characteristics, METHODS & MATERIALS to the . From the opposite lateral side, the needles were removed, threading the fishing line Study Site. This study was conducted in the waters through the musculature, and the two ends of the surrounding the Harbor and Jetty of the Research fishing line knotted then trimmed with diving shears. Station of Marine Science and Oceanography, STARESO (42.580278° 8.724167°) located on the Following the recording of the individual’s total length Northwest coast of Corsica, Calvi, France. The and the identifying color code of its tag, the tagged temperate marine habitat consisted of Posidonia individual was released within minutes of capture. If oceanica meadows, sand patches, cobble fields and the individual became temporarily incapacitated manmade breakers of boulders, lining the boundaries following handling, breathing was reestablished by of the harbor and jetty in rock walls. The coastline opening the mouth and moving the individual gently outside the harbor experiences low disturbance as the back and forth through the water to reestablish water island’s point provides some protection from wave passing over the gill arches. Within minutes, breathing action. Within the harbor, disturbance was extremely and recovery commenced. low. For the duration of the study (10/01/14-10/21/14), Capture Sites. Upon tagging and release, a 1m flagged water temperatures remained constant at 72°F±1° and (numbered) stake was planted at the point of capture. water visibility/clarity ranged 25-30m. Perpendicular to From this point of origin, a distance (to the nearest shore, permanent transects were located in the harbor 0.5m) and compass heading was taken in the direction (50m) and to the north wall of the jetty (85m) (see of the nearest meter marker upon one of the two Figure 1). My marine study was performed in the permanent transects. These measurements provide the range of 3-10 m depth. information necessary to geo-spatially map all capture Species. The red striped goatfish/, Mullus points. Capture sites were later used as an established surmuletus, inhabits sand and soft substrates less than point of reference on the map as an alternative to the 100m depth (Whitehead et. Al., 1986, Labropoulou et permanent transects, in measuring the location and al. 1997). Commonly found over sandy and rocky orientation of tagged goatfish re-sightings. Capture bottoms, goatfish demonstrate a preference for sand, sites will also be used as the “origin sighting” to be (Harrison et al. 2014). They use their chemosensory incorporated in the building of home range shapes – in barbels for shifting through sediment and detritus for the case that site fidelity is supported. benthic . Found throughout the Eastern Locational Observations. Following a 2-3 day Atlantic, down the English Channel to the Northern recovery period, during which time no data was taken coast of Africa including the Mediterranean and Black of tagged individuals, observational surveys of the Seas, red mullets are highly exploited by local and entire the Harbor and North Wall were conducted. commercial fishing industries (Bauchot 1987, When a tagged individual was located, its exact Labropoulou et al. 1997). location was recorded. Running the meter tape to the SITE FIDELITY nearest established marker, a distance and heading was recorded along with the individual’s identifying color Tagging. Goatfish were individually captured and code for each re-sight observation. If the mapped tagged SCUBA, using a casting net and 2-3 (2mm) points resulted in clustering, I could conclude that site beads, color sequenced and easily identifiable fidelity and a home range are present. underwater on SCUBA. Stretched between two SCUBA divers, the trailing net was draped over the Mapping Points. The locational points collected at foraging, stationary goatfish. Upon capture, one diver times of capture and all re-sightings were manually held the stationary; the second diver performed the mapped using the coordinate software of Google Earth tagging operation. Using two hand needles, sharing a Pro (2014). single strand of fishing line strung with the beads, the Mapping Home Ranges. If the points cluster, the diver inserted the two needles, side by side, home ranges will be manually drawn using the polygon simultaneously, through the dorsal musculature, close drawing feature software of Google Earth Pro, to create the Kernel Density Estimation (KDE) –the smallest The results of the observational study designed to map possible polygon using the observed locational points – the movements of the four tagged individuals strongly to best extrapolate the shape and area of the ’ support the hypothesis of site fidelity and home ranges home ranges (Moorcroft 2008). Between 5 and 15% of in goatfish, as evident by the clustering of re-sight the total observed points will be determined as outliers points in Figure 1. and shall be excluded from the calculated areas and shapes. Manual manipulation of the polygons assisted Mapping Locational Points in accuracy of the results due to field knowledge of site, including underwater obstructions and habitat compositions.

HOMING

Translocation. Goatfish were individually caught within the harbor, using a casting net (as described in Tagging), and transported 75m (or more) on SCUBA from the capture site, out of the harbor and to the 40m marking on the north wall transect where it was released. Upon the moment of release, divers remain for 1 minute, motionless and at depth, to prevent additional interference to the goatfish’s initial decision of direction. Following translocation, regular twice daily surveys were taken of the Harbor and North Wall. If a tagged individual was sighted, the locational point would be recorded (distance/heading) for mapping. If an individual is re-sighted within its established home range, we would conclude the re-sight as a return, Figure 1. The map represents all the locational points supporting the hypothesis of homing. recorded, along the two (red) transects. The yellow, green, blue and orange pins represent the re-sights of RESULTS the four mapped individuals with the red pins representing capture sites. SITE FIDELITY Mapping of Home Ranges Tagging. A total of seven goatfish were tagged over the course of 4 days. Following capture, handling and The smallest possible polygons, connecting the release, all individuals resumed their good health, respective re-sight points of each tagged individual to foraging, exhibiting similar behavior to non-tagged form their KDE home range were drawn for the four individuals, despite loss of some scales, with no individuals (see Figure 2). As the capture sites were heightened aversion to diver presence. included in total count of points as the original sighting point, thus increasing the range of total points to be 7- Locational Observations. The observational study of 16. The individual with the fewest points of 7 the seven tagged goatfish lasted thirteen days. Four of (Individual 4) determined a KDE of 85% [equated the individuals were located on numerous days of the from the fraction form of 6 of 7points] to eliminate study, and were subsequently mapped (Figure 2). The outliers. Thus is calculating the kernel estimate areas of total number of re-sights (points) ranged from 6 to 15. each individual’s home range, 85% of the total re-

Two tagged individuals were unable to be located sights were used. The average of all four KDE85% home following their initial re-sighting proceeding ranges resulted in (70.56m2 ± S.D. 56.36m2). capture/release. One individual was tagged and observed far outside of the harbor, and was ultimately deemed an outlier.

found to be a suitable species to be protected by spatial regulations, like an MPA. It could extrapolated that red striped goatfish would benefit similarly from such protection as MPAs. The conclusive findings of site fidelity and homing in goatfish, while informative as to their life history characteristics, pose an increased threat to the goatfish’s survival. As a highly exploited species within commercial fishing industries throughout the Mediterranean, northern coast of Africa and Eastern Atlantic, the goatfish is in danger of holding home ranges (Bauchot 1987, Labropoulou et al. 1997). If individuals manage to elude passing trawlers, or are too small for market and released, the fishermen need only return to the exact location sometime in the future to attempt to catch the individual goatfish that returned and remained at home. In the scope of fishing, movement is a key to the rate at which local populations can replenish following population depletions, as movement creates the spatial scale over which exploitation is manifested (Freiwald 2012). Without the movement of goatfish, outside of their fixed home ranges, I am concerned for their state Figure 2. The 85% Kernel Density Estimations of the of vulnerability to commercial exploitation. However, home ranges belonging to Individuals 1 – 4 as as the movement distances may be influenced by the produced by Google Pro Earth. species or habitat features, movement may differ between species near shore, shallow dwelling, deep HOMING dwelling or of larger body size (Freiwald 2012). Translocation. Individual 4 was captured twice and This study, short in duration, and lacking many transport 75m twice, from its capture site, outside its replicates, has the potential to become much stronger established home range (Figure 2) and returned within with repetition and expansion in total surveyed area. 24 hours both times. The calculated probability of that Whereas the methods were strong in design, the results individual goatfish being found within the area of the were weakened by the limited resources of man power. home range (21.17m2) out of the total area surveyed This study was executed by a single SCUBA diving (4190. m2) was 1.13%. The probability of that same team in the field, limited to two-three dives daily and individual returning a second time, in a row, was prone to ear infections which cost the study 0.01%. The results of the experiment designed to test if consistency and the potential for replicates in the lost goatfish will exhibit homing when moved outside its opportunity to researching for fourteen consecutive home range strongly supports the hypothesis that diving days. Future studies may be advised to employ homing is present in M. surmuletus, despite the low the help of multiple diving teams at one time, for number trials. tagging and observational purposes.

DISCUSSION In conclusion, by studying at the geo-spatial movements of red striped goatfish, strides can be made The red striped goatfish followed in this study to better understand the dynamics of the system as a demonstrated behaviors supportive of site fidelity and whole. Studies rooted in the residential influences of homing similar to their Hawaiian relatives, the white home range goatfish may now be explored, in relation saddleback goatfish ( porphyreus) (Meyer to other fishes, resources utilization or foraging 2000). Found to maintain small home ranges within the specialization. marine reserve, the white saddleback goatfish was ACKNOWLEDGEMENTS Moorcroft, P. Animal Home Ranges. 2008. Encyclopedia of Ecology. Ed. Jorgensen, S. & Fath, B. I thank all the diving volunteers and scientists, Vol. 1. Amsterdam: Elsevier. 174-180. especially Giacomo Bernardi, Pete Raimondi, Kate Melanson, Emma Chiaroni, and Daniel O’Shea, Whitehead, P., M. Bauchot, J. Hureau, J. Nielsen, E. without whom, this study would not have been Tortonese. 1986. Fishes of the North-eastern Altantic possible. and the Mediterranean, vol 2. UNESCO, Paris, pp. 515-1007. LITERATURE CITED Wiltschko, R., W. Wiltschko. 1978. Evidence for the Bingman, V. P. Migration, Navigation, and Homing. use of magnetic outward-journey information in Learning and Memory. Ed. John H. Byrne. 2004. 2nd homing pigeons. Naturwissenschaften. 65(2). 112-113 ed. New York: Macmillan Reference USA, 390-393. Worton, B. 1989. Kernel methods for estimating the Börger, L., B. Dalziel, and J. Fryxell. 2008, Are there utilization distribution in home-range studies. general mechanisms of animal home range behaviour? Ecology70:164-168 A review and prospects for future research. Ecology

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