Laboratory Reference No. 81 / 1 DFO 1liiMilifH'" "' 07018769

. MANUAL FOR IDENTIFYING LARVAL FISH OF THE MIRAM ICHI BAY , GULF OF ST . LAWRENCE

BY

D. B. LITTLE AND S. N. MESSIEH

"TH IS IS AN I NTERNAL UNPUBLISHED REPORT. IT IS NOT TO BE CITED WITHOUT PERM ISSION OF THE AUTHOR . DISTRIBUTION IS NOT LIMITED . 11

FI SH. D1111s1. 04'

Resource Branch, Fisheries Management Maritimes

Fisher\eS

Bedford Institute of Oceanography Biological St ation P.O. Box 1006 St. Andrews Dartmouth, QL , B 2Y 4A2 Canada, EOG 2XO 626 . 5 N6 L57 GULF FISHERIES LIBRARY FISHERIES & OC8\,~S BIBLIOTHEQUE o;:s PECHES GOLFE PfC'-IE3 ET rcEMIS N~T TO BE CITED WITHOUT PERMISSION OF AUTHOR

MANUAL FOR IDENTIFYING LARVAL FISH OF THE

MI-RAMICHI' BAY, GUL,F OF ST. L.AW'R~NCE

by

D.B. Little1 and S.N. Messieh Fisheries and Oceans Marine Fish Division Bedford Institute of Oceanography Dartmouth, N.S.

1 - on contract to Marine Fish Division -1- \ .

INTRODUCTION

During the spring and fall of 1979 and spring of 1980 icthyoplankton surveys were conducted in the Miramichi Bay of New Brunswick and the northern area - Gulf of St. Lawrence (Figure 1). The objective of these surveys was to determine the distribution and abundance of herring larvae, however, other species of fish larvae were also collected. Twenty-one species were identified during these collections. Due to the scarcity of references on larval fish in this area, ident­ ification of the species was not easy. The only available reference on fishes in the Miramichi Bay is by McKenzie (1959). His paper contains a checklist of the adult fish found in the area and their fisheries without reference of the larvae. Descriptions of larval fish species collected in neighbouring waters are found in a few scattered references. The species described were of the four­ beard rockling (Faber 1976a), artic and radiated shanny (Faber 1976b), capeli.n . (Templeman 1948), sculpin (Khan 1971), yellowtail flounder, american plaice (Van Guelpen 1980), and mackerel larvae (Berrien 1975). A paper by Dannevig in 1914 on "Canadian Fish Eggs and Larvae 11 contains sketches of many of the same species collected during the Miramichi surveys but did not contain des­ criptions or identifying features of these larvae. A review of published work on larval identification for Northwest Atlantic, by the U.S. Fish and Wildlife Service (Anon 1978) was available and consulted frequently. However, this publication refers to larvae collected in the Mid-Atlantic Bight, and des­ criptions given were not always congruent with those of our samples. This report is designed to aid those engaged in larval fish identification in the Miramichi Bay or nearby waters in the Gulf of St. Lawrence. The manual includes descriptions of 21 larvae and a key for their identification. It should be remembered that the descriptions and key apply to those samples ex­ amined during these surveys. As pigmentation patterns may vary with larval size, descriptions based on this character, for sizes outside the size range examined, should be taken with care.

MATERIALS AND METHODS

Sampling stations in the surveyed area are shown in Figure 1. At each station a step oblique tow was conducted for a duration of 12 minutes, starting as close as possible from the bottom hauling up to the surface. Sampling gear consisted of nets of two mesh sizes (.333 mm and .505 mm) mounted on a .61 meter bongo frame. Samples were immediately washed with sea water and preserved in 5% formalin. Tables 1 and 2 present location and date of fish samples used in identification as well as the size range of the larvae collected. Sorting of larvae was carried out in a gridded petri dish under a binocular microscope. Identified larvae were separated by species, counted and placed in separate labelled vials. Drawings of larvae were made to scale by the use of a drawing tube attached to the microscope. Pigmentation was of much use in ident­ ification. A description of melanophyte types is presented in Table 3. An -2- • > identification key based on the most distinguishing characteristics of species examined was constructed. A reference collection of all species collected and identified is available at the Marine Fish Division, BIO, Dartmouth, Nova Scotia. -3- ' .

Key for Identifying Fish Larvae in the Miramichi Bay

1. Narrow, elongate larvae. 2 Deepened bodies with tapering tail, gut relatively short. 6

2. Anus located 3/4 - 4/5 the length of the body. 3 Anus located just beyond the midpoint of the body. 5 3. Pigment dashes on anterior half of gut run dorsally in a double row, abruptly changing at the midpoint to a ventral position, anus located 4/5 the length of body. Herring Pigment dashes ventrally in a single row along entire length of gut, anus located approximately 3/4 the length of body. 4 4. Thin thread-like larvae. Capel in Thread-like larvae, but slightly deeper. Smelt 5. Stellate melanophores on the dorsal surface of the gut; ventral surface virtually unpigmented except for a small ventro-medial strip located just behind the pectorals. Sand lance Very light pigment granules arranged along the ventro-medial surface of the gut, continuing postanally to the caudal end, few light pigment dots scattered on dorsal surface. Rock gunnel 6. With spines . 7 Without spines. 8 7. Long, heavily spined body; large alligator-like head; Alligator fish huge fan-like pectorals, heavily pigmented at the tips. Spines restricted to head region; stellate melanophores on gut. Sculpin

8. With postanal bars or bands. 9 Without postanal bar or bands. 15 9. Has 3 evenly spaced postanal bands. 10 Has postanal bar or bars. 11 10. Extension of bands into finfold; no interband pigment; vent located immediately behind the yolk sac. Witch flounder No extension of bands into finfold; scattered interband pigment may in some cases merge the bands; space between yolk sac and vent. A. Plaice 11. Pigment clustered on head. 12 Little or no pigment on head. 14 12. A single dorsal bar of pigment present about mid-body; large fan like ventral fins located below the pectorals, usually Fourbeard Pigmented. rockling -4- • j

More than one postanal bar 13 13. Two evenly spaced dorsal bars, and one ventral bar; ventral bar adjacent to the posterior most dorsal bar; pigmentation light. Silver hake Two evenly spaced dorsal bars, with two corresponding ventral bars; ventral bars longer than dorsal bars. Cod 14. A single, postanal dorso-ventral pair of bars located midway between vent and caudal end; bars may appear as large stellate melanophores; single stellate melanophore situated just behind the head, and ventrally near the caudal end; gut pigmentation is mainly dorsal with a small ventral spot near the vent. Cunner Six pigment bars, four ventral and two dorsal; the two dorsal bars are located adjacent to the second and third ventral bars; stellate melanophores on the dorsal surface of the gut with a pigment on the midline of the body. Yellowtail flounder 15. Stout, deep gut. 16 Na ~ row more elongate gut. 20 16. Adsence of any dorsal gut pigment; pigmentation is extirely ventral along the gut and body contour. Winter flounder Presence of dorsal gut pigment. 17 17. Presence of stellate melanophores on the posterior side of the pectoral fins. Seas nail Absence of pigment on pectoral fins. 18. Absence of pigment on head and tail region; scattered melanophores at mid-body only. Windowpane flounder Presence of pigment on head and tail region. 19 19 . Pigmentation heavy on top of head and along dorsal surface of gut. Mackerel Pigmentation sparse on head and dorsal surface of the gut. Silverside 20. Postanal pigment consists of mid-lateral melanophores regularly arranged, in a series of dashes, between the myomeres of the body; in larger specimens a double row of melanophores may be seen on the bodies dorsal contour. Arctic shan Postanal pigment has no regular arrangement; a single large mid­ ventral stellate melanophore present on the anterior most half of the gut. Radiated shanny -5- ' '

Acknowledgments

?everal people contributed to the sampling and sorting of the collection used for this identification. This study was conducted as part of the Miramichi Bay Project for which Marilyn Marley, Leslie Demal, Robert Pottle, Paul MacPherson and Dave Moore carried out most of the field work. Randy Losier sorted the 1979 collection, while Doug Markle and Lou Van Guelpen, of the Huntsman Marine Laboratory, St. Andrews, N.B. were occasionally con­ sulted for checking the identification. The figures are drawn by Peggy Mccalla and the text typed by Donna King. -6- . '

References

Anon. 1978. Development of Fishes of the Mid-Atlantic Bight. An Atlas of egg, larval and juvenile stages. vol I-IV. Fish and Wildlife Service, U.S. Department of the Interior. Berrien, P. 1975. A Description of Atlantic Mackerel, Scomber Scombrus, Eggs and Early Larvae. Fishery Bulletin. 73 ( 1): 186-192. Bigelow and Schroeder. 1953. Fishes· of the Gulf of Maine. Fishery Bulletin No. 53. Fish. Bull. of the U.S. Fish and Wildlife Service. Dannevig, A. 1919. Fish eggs and larvae, p. 1-80. In J. Hjort Canadian fisheries expedition, 1914-15, in the Gulf of St. Lawrence and Atlantic waters of Canada. Dept. Nav. Serv. Can., King's Printer, Ottawa, Ont. Faber, D. 1976(a). Hyponeustonic Fish Larvae in the Northumberland Strait During Summer 1962. J.F.R.B. Canada 33(6): 1167-1174. Faber, D. 1976(b) . Identification of Four Northern Blennioid Fish Larvae in the Canadian Atlantic Ocean (Stichaeidae, Lumpenidae). J.F.R.B. Canada 33 (8): 1798-1802. Khan, N. 1971. Comparative morphology and ecology of the pelagic larvae of nine Cottidae of the northwest Atlantic and St. Lawrence drainaoe. Ph.D Thesis, Univ. Ottawa, Canada. - Leim, A.H. and W.B. Scott. 1966. Fishes of the Atlantic Coast of Canada. FRS Bul 1. 155. McKenzie, R.A. 1959. Marine and Fresh Water Fishes of the Miramichi River · and Estuary, N.B. J. Fish. Bd. Canada, 16(6). Templeman, W. 1948. The Life History of the Capelin (Mallotus villosus 0.F. MUller) in Newfoundland Waters. Bull. Nfld. Gover. Lab. (17): 1-151. Van Guelpen, L. 1980. Taxonomic variability and criteria for distinguishing metamorphosing larval and juvenile stages of Limanda ferru inea and Hippoglossoides platessoides (Pisces: Pleuronectidae from the Scotian Shelf. Can. J. Zool. 58 (2): 202-206. -7- ' .

ble 1. List of larval fish species collected during 4 cruises in 1979 and 1980.

Spring 1979 Fa 11 1979 Spring 1980 Size SPECIES June Aug. Sept. May - June Range (mm)

Sand lance x x 2.5 - 10.5 Alligatorfish x x 18.0 Herring x x 5.5 - 10.4 Sculpin x x 4.3 - 6.2 Fourbeard rock ling x x x 4.5 Cod x x x 2.8 - 3.7 Witch flounder x 5.8 American plaice x x 2.8 - 6.4 ellowtail flounder x x 6.5 Seasnail x x 2.8 5.0 Capel in x 7.5 - 10. 5 Atlantic silverside x 4.3 Si 1ver hake x 2.5 Smelt x x 4.2 - 8.1 Rock gunnel x 27.0 Winter flounder x x x 2.0 - 7.9 Mackerel x 5.6 Windowpane flounder x x x 4.0 Arctic shanny x x 11. 0 - 17.0 Radiated shanny x x x x 5.0 - 6. 7 unner x x x 5.0 -8- . ' Table 2. Date and location of larval fish collected

Species Date and Location of collection (month/year) (see map for location)

Sand lance June 1979 inner and outer Miramichi Bay May-June 1980 June 1979 northern Northumberland Strait Point Escuminac to A11 i gatorfi sh June 1979 inner and outer bay, northern Northumberland Strait between Point Escuminac and Point Sa pin June 1980 outer Miramichi Bay Herring June 1979 May-June 1980 inner and outer Miramichi Bay June 1979 northern Northumberland Strait, Point Escuminac to Kouchibouquac Sculpin June 1979 May-June 1980 outer bay June 1979 northern Northumberland Strait, Point Escuminac to Kouchibouquac Aug-Sept 1979 outer Miramichi Bay Aug 1979 northern Northumberland Strait, Point Escuminac to Point Sapin Cod June 1979 outer Miramichi Bay May 1980 June 1980 inner and outer Miramichi Bay June 1979 northern Northumberland Strait, Point Escuminac to Richibucto Aug 1979 northern Northumberland Strait, Point Escuminac to Point Sapin Witch flounder Aug 1979 northern Northumberland Strait, Point Escuminac to Point Sapin American plaice June 1979 outer Miramichi Bay and northern NorthumbPrlAn < Strait, Point Escuminac to Kouchibouquac May-June 1980 inner and outer Miramichi Bay Yellowtail flounder June 1979 June 1980 outer Miramichi Bay June 1979 northern Northumberland Strait, Point Escuminac to Kouchibouquac -9- ' '

' t Seas nail June 1979 inner and outer Miramichi Bay May-June 1980 June 1979 northern Northumberland Strait, Point Escuminac to Richibucto Capel in June 1979 inner and outer Miramichi Bay and northern Northumberland Strait, Point Sapin to Ri chi bucto Atlantic silverside June 1979 outer Miramichi Bay and northern Northumberlar Strait, Point Sapin to Richibucto Si 1ver hake June 1979 inner Miramichi Bay and northern Northumberlan Strait, Point Sapin to Kouchibouquac Smelt June 1979 inner and outer Miramichi Bay May-June 1980 June 1979 northern Northumberland Strait, Point Escuminac to Richibucto Rock gunnel June 1979 inner and outer Miramichi Bay and northern Northumberland Strait, Point Escuminac to Point Sapin I Winter flounder June 1979 May-June 1980 inner and outer Miramichi Bay June 1979 northern Northumberland Strait, Point Escuminac to Richibucto Aug 1979 northern Northumberland Strait, Point Escuminac to Point Sapin Mackerel June 1979 northern Northumberland Strait, Point Sapin to Richibucto Windowpane flounder June 1979 northern Northumberland Strait, Point Sapin to Richibucto Aug 1979 inner and outer Miramichi Bay and northern Northumberland Strait, Point Escuminac to Point Sapin Sept 1979 outer Miramichi Bay Arctic shanny June 1979 outer Miramichi Bay May 1980 June 1979 northern Northumberland Strait, Point Sapin to Richibucto Radiated shanny June, Aug 1979 outer Miramichi Bay June 1979 northern Northumberland Strait, Point Escuminac to Richibucto -10- .. Radiated shanny (cont'd) Aug 1979 northern Northumberland Strait, Poi~t Escuminac to Point Sapin Sept 1979 outer Miramichi Bay May-June 1980 inner and outer Miramichi Bay Cunner June, Aug 1979 outer Miramichi Bay Aug 1979 northern Northumberland Strait, Point Escuminac to Point Sapin Sept 1979 inner and outer Miramichi Bay _.:.. Table 3. Types of Melanophore Arrangements -11-

STELLATE Star-like black chromatophores, expanded pigment Solitary cells. These could be solitary e.g. melanophores along guts of sand lance (p. 19 ) and Radiated Cluster shanny (p. 53), or aggregated in clusters, e.g. melanophores on head of mackerel (p. 47).

PUN CT ATE Contracted black chromatophores, pigment concen­ : ~.. .: Spots trated in the center of cells. These vary in size from large spots (e.g. melanophores on postanal Granules area of sculpin, (p. 25 ) to small l ight granular­ like dots (e.g. melanophores on postanal area of rock gunnel, (p. 21 )).

LINEAR ARRANGEMENT Melanophores are arrayed in lines. These could be Strip long strips (e.g. media-ventral strip on the anterior part of guts of sand lance (p. 19) and Hori zonta 1 dashes arctic shanny (p . 51) or i n short strips which could be oriented horizontally as in smelt (p. 17) ////// Oblique dashes or obliquely as in arctic shanny (p. 51). .. /: '.' BARS AND BANDS Melanophores are mainly stellate shape arranged

Bar in narrow horizontal bars, e.g. postanal bars on t'h\» cod (p. 35) and fourbeard rockling (p. 31 ). i·,. .. Band Sometimes these bars completely encircle the body of larva forming a band (e.g . .American plaice

(p. 29 ) ) . F•' t'·' -12-

Atlantic herring (Clupea harengus) The herring larvae is a long thin, thread-like, larvae readily identified by its anal position and its characteristic pigmentation . The vent is located about 4/5 the length of the body from the anterior end, and opens at the margin of the finfold. Pigmentation is made up of a series of pigment dashes running down the length of the gut. In the anterior half of the gut the pigments run dorsally in a double row of dashes. At approximately the midpoint of the gut the pigments abruptly turn to the ventral position where the two rows of pig­ ments are brought closer together, following what may now appear as a single row running down to the anus . Other, less characteristic pigmentation, that may also be seen on a herring larva of this size range, is a sprinkling of dots near the base of the caudal fin rays, and a couple of paired pigment dashes found ventrally in the thoracic region. Similar Species: capelin, smelt - 13-

HERRING

8.5mm -14-

Capelin (Mallotus villosus) Very similar to the larvae of herring and smelt is that of capelin. These three species may be the most easily confused of all the species found, having characteristic elongated, narrow bodies, a gut that extends approximately 3/4 the length of the body, and somewhat similar pigmentation. Capelin larvae have the same single ventro-medial row of pigments running along th~ gut, seen in smelt; and similar doub~e media-lateral rows of melanophores on the first half of the gut as observed with herring larvae. The branchial cavity and isthmus of capelin are also pigmented by a series of paired melanophores. Differentiating between herring and capelin larvae may be easier when dealing with larger specimens (15 mm). It's at this stage that capelin larvae will have started to develop an adipose fin, and its jaws may become more protrusive. However, distinguishing between the very similar smelt and capelin larvae may not be so simple. One method that has been suggested is Templemans body length to body depth ratio; where at a corresponding length, the body of a smelt is much deeper than that of capelin (Templeman 1948). Similar Species: herring, smelt -15-

CAPELlN

------

10.5mm -16-

Smelt (Osmerus mordax) Smelt is another long thin larvae and because of its anal position, being located about 3/4 down the length of the body, could at first glance be confused with herring or capelin larvae. A distinctive difference between herring and smelt exist with characteristic pigmentation patterns. Pigment­ ation consists of a series of short dashed located ventrally in a single row along the entire gut. The pigments may also extend postanally in the form of pigment spots or continue along as dashes. Two or three pairs of shorter pigment dashes are also present in the thoracic region, similar to those found in herring. Another difference between the smelt and herring larvae is that the smelt's lower jaw may protrude farther than that of herring. Less obvious differences exist between smelt and capelin larvae, both having very similar pigmentation. Perhaps the easiest way of distinguishing the two larvae is using Templeman's body depth to length ratio, where the body of smelt larvae deepens, more rapidly than that of capelin. This phen­ omea is something observed more readily in specimens larger than 15 millimeters (Templeman 1948). Smelt was a very comnon species caught during the spring survey. High concentrations of smelt larvae were particularly found in the inner bay region where waters are less saline. Similar Species: herring, capelin - 17 -

SMELT

6.\mm -18-

Sand Lance (Ammodytes ~.) The largest specimen of sand lance encountered during the survey was 10.5 mm total length, however, most larvae averaged about 4.5 mm. Sand lance in another thin white larva captured and was identified as in the case of herring and smelt, by the anal position and pigmentation. The vent opens at 'the base of the fin fold just beyond the midpoint of the body. Along the dorsal surface of the gut runs a double row of stellate melanophores, while a series of smaller punctuate melanophores, running along the ventral surface of the body from the vent to just anterior to the caudal fin, makes up the postanal pigmentation. In the smaller sizes (up to 11 mm) the head is completely unpigmented with only a small strip of pigment present ventrally in the thoracic region. Several small melanophores may also be present at the base of the caudal fin rays. Similar Species: rock gunnel -19-

SANO LANCE

10.5 mm -20-

Rock Gunnel (Pholis gunnellus) The rock gunnel has a long thin threadlike larvae very similar to sand lance (Jlmmodytes ~.). The anal position for both species is almost identical, opening at about the mid-point of the body. However, the vent in rock gunnel opens at the margin of the finfold opposed to opening at its base as seen in sand lance. The two can more readily be distinguished by gut pigmentation, which runs ventrally in a single row for rock gunnel, and dorsally in a double row for sand lance. In larger rock gunnel specimens a few dorsal pigment spots may appear near the vent opening, and just posterior to the pectoral fins. Postanal pigmentation is the same for both species, consisting of scattered light pigment running ventrally along the body. Similar Species: sand lance -21-

' '

ROCK GUNNEL

(§;,, I . ?.. f--1 -==-~

2.?mm -22-

Alligatorfish (Aspidophoroides monopterygius) A single, large alligatorfish larvae was the most easily recognized of all the larvae collected. About 18 mm in total length it was characterized by a large alligator-shaped head, huge wing-like pectoral fins and a long narrow heavily spined body. Pigmentation was prominent over the entire body, particularly along the ventral surface and at the tips of its winged pectoral fins. From the ventral pigmentation three eveffly spaced bands arise, somewhat like those found in american plaice larvae. Similar Species: ALLlGATORFlSH

' \

IS mm -24-

Sculpin (Cottidae)

Although ~ ot identified to the species level, representatives of the sculpin f amily \were collected during the survey . Pigmentation is simple and confined to large stellate melanophores found concentrated on the short stout gut, with only a sprinkling of postanal pigment granules from the vent to the tail. It is, however, their large heads, compact bodies, opercular spines, and fan-like pectoral fins that readily distinguish them as scul pins. Similar Species: seasnail ' -25-

SCULPIN

5.5mm -26-

Witch Flounder (Glyptocephalus cynoglossus) Witch flounder has a larval stage quite similar to that of the american plaice, in so-much that both species have the same three evenly spaced postanal pigment bands. The two can be distinguished however by the band extension into the finfold and the absence of any interband pigmentation found only in witch flounder larvae. The vent of witch flounder opens at the margin of the finfold. Similar Species: american plaice, yellowtail flounder -27-

WITCH FLOUNDER

5.8mm -28-

American Plaice (Hippoglossoides platessoides) All plaice larvae captured were very young or newly hatched larvae, averaging about 5.0 rrun in total length. This species is recognized by the presence of three evenly spaced postanal pigment bands. Secondary pigment clusters are found on the gut and vent as well as a small ventral bar of pigment located just behind the anus. A scattering of melanophores may also be found between the postanal bands, in some cases seeming to merge the bands into one large cluster of pigment. A species with a somewhat similar pigmentation pattern is the witch flounder (Glyptocephalus cynoglossus). Although both species have the same three postanal bands of pigment, the witch flounder can be distinguished by the extension of the bands into the finfold together with the adsence of any inter-band pigment. Similar Species: witch flounder, yellowtail flounder -29-

AMERICAN PLAICE

\ \ 5.0mm -30-

Fourbeard Reckling (Enchelyopus combrius) The rockling larva of size 4.5 mm can be recognized by the arrangement of pigments in four distinct areas of the body. The first is clusters of pigment on the head and neck area; the second is a concentration of melano­ phores on the dorsal surface of the gut, extending down to the vent; the third area is a postanal dorsal bar of pigment found midway between the vent and the tip of the caudal end; the fourth area is perhaps the most distinguishing of all cahracteristics, the presence of pigmented fin rays on the 1arge fan like ventral fin. Similar Species: white hake -31-

FOURBEARD ROCKLING'

4.5mm -32-

Silver Hake (Merluccius bilinearis) Although considered rare for the Gulf area, and probably a stray, a single silver hake larva measuring 2.5 mm in total length was found in the 1979 survey. The distinguishing feature of the species is pigmentation located on the dorsal surface of the gut, a small sprinkling on the head and just behind the head, as well as 3 postanal bars. The postanal bars consists of 2 dorsal and one ventral bar. The ventral bar being located opposite the most anterior dorsal bar. There is also a light pigment spot, that was difficult to make out, on the caudal end . Some confusion may arise between the pigmentation of silver hake larvae and cod larvae. This is particularly true when identification is made from specimens preserved in formalin for long periods ( > 1 year), resulting in pigment fading. Similar Species: cod -33-

SILVER HAKE

•

2.5mm -34-

Atlantic Cod (Gadus morhua) Most cod larvae caught averaged approximately 3.0 nm in total length, and were easily recognizable by a characteristic pigmentation pattern. Aside from a scattering of pigment on the head and a dorsal row of melanophores on the gut extending down to the vent, four definite postanal bars can be recog­ nized. This postanal \Pigmentation is comprised of two ventral bars, each with an adjacent, yet shor~ , dorsal bar. A reduced fifth pigment bar, often made up of only a few pigment granules, is found on the ventral tip of the caudal fin. Although not collected during the survey and probably not a Gulf spawner, pollack larvae (Pollachius virens) has a somewhat similar pigmentation to cod. The difference between the two species is that pollock's dorsal bars are longer than their corresponding ventral bars. In later stages, when the larvae reach lengths of 7-10 mm, a fusion of these bars occurs making identification with respect to pigment difficult. Similar Species: pollack, silver hake -35-

COD

3.6mm -36-

Cunner (Tautogolabrus adspersus) Easily recognizable by small aggregations of melanophores on the gut and body. Pigmentation is found dorsally on th.e gut with only a tiny ventral spot near the vent opening. Postanally, about mid-way between the vent and the tail, a dorso-ventral pair of pigment bars are found. Other stellate melanophores can be found ventrally near the tip of the caudal end and on the head. Similar Species: mackerel -37-

GUNNER

5.0mm -38-

Yellowtail Flounder (Limanda ferruginea) Only one yellowtail larvae was found in the collection, measuring 6.5 mm in total length. It was identified primarily by the presence of its six postanal pigment bars; 4 ventral and 2 dorsal. The 2 dorsal bars are located opposite the 2nd and 3rd ventral bars, with only scattered pigment along the midline of the body . Numerous stellate melanophores are also present on the dorsal surface of the gut near the vent opening, as well as a row of smaller pigment dashes running ventrally from the vent to the thoracic region. Similar Species: winter flounder, american plaice - 39-

• , I

YELLOWTAIL FLOUNDER

6.5mm -40-

\ .

Winter Flounder (Pseudopleuronectes americanus) Winter flounder was the most abundant species of fish larvae found during the spring survey, ranging in size from 2 to 8 mm in total length. The most distinguishing characteristics for this species are the punctate melanophores that run ventrally in a double row along the postanal region of the body, as well as the ventral portion of its coiled gut. Other than a cluster of light pigment spots found about 2/3 down the length of the body, there is little or no pigment on the rest of the body. Similar Species: yellowtail flounder -41-

' ' I

WINTER FLOUNDER

...... ~·.

4.9mm

7.9mm -42-

Seasnail (Liparis .?12£.) The larva is distinguished by both its pigmentation pattern and its general body shape. The seasnail is recognized as having a large rounded head and large eyes, followed by a short stout gut with a vent that opens at the margin of the finfold. From the enlarged head and trunk, the body then tapers off sharply to the caudal fin. With younger larvae the majority of pigment is confined to clusters of stellate melanophores on the gut and the posterior side of the large pectoral fins. Postanally there are scat­ tered, punctate, melanophores running ventrally along the body contour, with only a few pigment spots media-laterally just behind the gut. The larger specimens (6-7 mm), a concentration of pigment was found in this mediolateral region, as well as on the lower jaw and ventrally in the thoracic region. Similar Species: sculpins -43 -

' '

SEA SNAIL

\ 3.5mm -44-

' ,;.

Windowpane Flounder (Scophthalmus aguosus) This larva has an e ~ tremel ~ simple arrangement of pigments . Heavy pigmentation starts just behind the pectoral fins and extends about half way down the body, where it abruptly ends. The head and tail are virtually free of any pigmentation. The body of the larva is short and deep, with a vent that opens at the margin of the finfold. Similar Species: -45-

. ' '

WINDOWPANE FLOUNDER

.. ,. '

~ . • '. \> : ->· . • ·~ r. . ...'". ~

.. _,

. ' . '.

4.0mm

~ . ,• . :' . ·"· .·.

· .. · ... _,'·:. _· .... •

. ,, I .: • • < ! : .-. ·-:.1 .> -46-

f I

Mackerel (Scomber scombrus) The mackerel larvae of size 5.6 mm was identified by the pigmentation on the head, gut, and along the dorsal and ventral contours of the body. Pigmentation of the head is quite heavy with a large cluster of stellate melanophores on the crown and a scattering of pigment between the eyes and posteriorly in the thoracic region. Gut pigmentation is also heavy, but only on the dorsal surface where stellate melanophore are aggregated. Postanally melanophores run along the dorsal and ventral surface of the body, with the ventral pigment extending further forward than the dorsal.

Similar Species: cunner (< 5 mm) -4 / -

' I I

MACKEREL

I .

5.6 mm -48-

I '

Atlantic Silverside (Menidia menidia) A silverside larva of 4.3 mm was identified by its thin, long tapering body, and short gut. Pigmentation consisted of a few large melanophores on top of the head scattered pigment along the dorsal and ventral surface of the gut, and a ventral row of small punctate melano­ phores in the postanal region. -49-

SILVERS/OE

4.3mm -50-

I <

Arctic Shanny (Stichaeus punctatus) Arctic shanny larvae are somewhat similar to smelt and herring. Even though the body may be somewhat laterally compressed, it is still quite narrow and long, and doesn't tend to taper off so readily in the postanal region. The vent of arctic shanny, however, opens in the first half of the body. Head and gut pigmentations are mainly dorsal, made up of aggregations of large stellate melanophore. A single long, ventromedial melanophore can also be seen on the most anterior half of the gut. It's in the postanal pigment that we perhaps find the most identifying features, that is the pre­ sence of a regularly arranged series of pigment dashes situated between the myomeres of the body. Other postanal pigmentation can be seen as a l i ne of mid-ventral punctate melamophores running along the body contour. In more developed specimens a double row of melanophores may also appear on the dorsal contour of the body. Another commonly found species, very similar to Arctic Shanny and may be confused with it, is the radiated shanny (Ulvaria subbifurcata). The difference between the two speci es lies in the arrangement of the postanal pigment. Where arctic shanny definitely have a regular arrangement of pig­ ment, the radiated shanny is lacking (Faber 1976(b)). Similar Species: radiated shanny ' , ~ r

ARCTIC SHANNY

15mm -52-

' .

Radiated Shanny (Ulvaria subbifurcata) Aside from the location of some postanal pigments, the radiated shanny larva looks very similar to that of arctic shanny (Stichaeus punctatus). Both species have similar pigment clusters dorsally on the gut and head, and a ventro-medial pigment strip on the anterior most half of the gut. They differ, however, in the postanal region with respect to the arrangement of pigment dashes alson the lateral areas of the body. Arctic shanny larvae were noted as having a regular arrangement of dashes, located between the myomeres, while in radiated shanny the dashes are not so regular but may only be random extensions of mid-ventral pigment. Radiated shanny larvae also have a large mid-ventral stellate melanophore on the most anterior half of the gut, directly below the pectoral fins, that is not seen in arctic shanny. Similar Species: arctic shanny