Michael P. Fahay

Composition, abundance, biomass, and production of macrofauna in a New England estuary: comparisons among eelgrass meadows and other nursery habitats

Quantitative suction sampling was used to characterize and compare the species composition, abundance, biomass, and secondary production of macrofauna inhabiting intertidal mud-flat and sand-flat, eelgrass meadow, and salt-marsh-pool habitats in the Nauset Marsh complex, Cape Cod, Massachusetts (USA). Species richness and abundance were often greatest in eelgrass habitat, as was macroinvertebrate biomass and production. Most striking was the five to fifteen times greater rate of annual macrofaunal production in eelgrass habitat than elsewhere, with values ranging from approximately 23–139 g AFDW m2 yr−1. The marsh pool containing widgeon grass (Ruppia maritima) supported surprisingly low numbers of macroinvertebrates, probably due to stressfully low dissolved oxygen levels at night during the summer. Two species of macroinvertebrates, blue mussels (Mytilus edulis) and to a lesser extent bay scallops (Argopecten irradians), used eelgrass as “nursery habitat.” Calculations showed that macroinvertebrate production is proportionally much greater than the amount of primary production attributable to eelgrass in the Nauset Marsh system, and that dramatic changes at all trophic levels could be expected if large changes in seagrass abundance should occur. This work further underscores the extraordinarily large impact that seagrass can have on both the structure and function of estuarine ecosystems. *** DIRECT SUPPORT *** A01BY070 00006

Fishes and Decapod Crustaceans of Cape Cod Eelgrass Meadows: Species Composition, Seasonal Abundance Patterns and Comparison with Unvegetated Substrates

Bimonthly trawl samples from eelgrass and nearby unvegetated areas on Cape Cod, Massachusetts, showed greater species richness in eelgrass meadows relative to unvegetated areas, and greater summer abundance in vegetation for decapod crustaceans and fishes. The composition of eelgrass-associated decapods and fishes was dominated by cold-water taxa and was strikingly different from that of the better studied eelgrass meadows of the mid-Atlantic coast. Four of the eight decapod species collected, including the second and third most abundant taxa, do not even appear in collections reported from Chesapeake Bay eelgrass meadows. Similarly, 10 of the 22 fish species taken, including the first and sixth most abundant species, are not reported from Chesapeake Bay eelgrass samples. Cape Cod eelgrass beds seem to play a nursery role for several commercially important fish species, although the nursery function is less obvious than in previously studied mid-Atlantic eelgrass meadows.

Use of salt-marsh peat reefs by small juvenile lobsters on Cape Cod, Massachusetts

The habitats utilized by small juvenile (<40 mm carapace length, CL) lobsters (Homarus americanus) are poorly known. We discovered and studied an undescribed juvenile lobster habitat in Nauset Marsh, Cape Cod. Juvenile lobsters (X=26.7 mm carapace length, 6 to 72 mm, n=38) were collected from suction samples primarily 0144 01 in “peat reef” habitats during the period from August 1985 through October 1986. The reefs consisted of large blocks ofSpartina alterniflora peat that had separated from the marsh surface and fallen into adjacent subtidal marsh channels. The smallest lobsters (6 to 7 mm CL) were collected from peat reefs in October 1985, and April and July 1986. In these habitats, juvenile lobster density averaged 2.5 individuals m−2 (range 0–5.7) in suction samples. Peat reef habitats occur in other salt marshes in the northeastern United States and may be an important nursery habitat for small juvenile lobsters.

SEASONAL DISTRIBUTION AND ABUNDANCE OF FISHES AND DECAPOD CRUSTACEANS IN A CAPE COD ESTUARY

Abstract Sampling in several habitat types (sand/mud, eelgrass, sand, gravel, macroalgae/mud) during all seasons with a variety of gears in Nauset Marsh, Massachusetts during 1985–1987 found a fauna consisting of 35 fish and 10 decapod crustacean species. Although most of the abundant species were found in several habitat types, species richness and habitat use appeared to be highest for vegetated habitats (eelgrass, macroalgae). The fishes and decapods were numerically dominated by cold-water taxa; however, numerous fish species, represented by rare individuals of predominantly southern forms, enriched the fauna. Species composition of Nauset Marsh could be distinguished from estuaries south of Cape Cod and even from the south shore of the cape. Both fishes and decapods were most abundant during the summer, apparently due to the contributions from spring and summer spawning in the estuary and the adjacent Atlantic Ocean. The location of Nauset Marsh and other estuaries on Cape Cod provide a unique opportunity to evaluate the importance of this region as a faunal boundary to estuarine species.

Development and distribution of cusk eel eggs and larvae in the Middle Atlantic Bight with a description of Ophidion robinsi n. sp. (Teleostei : Ophidiidae)

the wandering garter snake, Thamnophis elegans vagrans. Toxicon 19:831-839. , S. P. MACKESSY, AND K. V. KARDONG. 1991. The unique Duvernoys secretion of the Brown Tree Snake (Boiga irregularis). Ibid. 29:532-535. WEINSTEIN, S. A., D. CHISZAR, R. C. BELL, AND L. A. SMITH. 1991. Lethal potency and fractionation of Duvernoys secretion from the brown tree snake Boiga irregularis. Ibid. 29:401-407. YOSHIE, S., M. ISHIYAMA, AND T. OGAWA. 1982. Fine structure of Duvernoys gland of the Japanese colubrid snake, Rhabdophis tigrinus. Arch. Histol. Japan 45:375-384. --, T. OGAWA, AND T. FUJITA. 1988. Histochemical, immunohistochemical, and ultrastructural characteristics of nerves in the Duvernoys gland of the Japanese colubrid snake, Rhabdophis tigrinus. Arch. Histol. Cytol. 51:459-466.

Life history and food habits of the grubby, Myoxocephalus aeneus (Cottidae), in a Cape Cod estuary

havioral interactions between two desmognathine salamander species: importance of competition and predation. Ecology 68:1453-1458. SIMON, M. P. 1984. The influence of conspecifics on egg and larval mortality in amphibians, p. 65-86. In: Infanticide, comparative and evolutionary perspectives. G. Hausfater and S. Blaffer-Hrdy (eds.). Aldine Publ. Co., New York, New York. SOKAL, R. R., AND F.J. ROHLF. 1981. Biometry: the principles and practice of statistics in biological research. 2nd ed. W. H. Freeman, San Francisco, California.

Ontogenetic evidence supporting a relationship between Brotulotaenia and Lamprogrammus (Ophidiiformes: Ophidiidae) based on the morphology of exterilium and rubaniform larvae

Analysis of the “Dana” collection of larval fishes yielded 36 exterilium larvae and 17 rubaniform larvae, referable to the Ophidiidae. Both larval types reach large sizes before transformation and are characterized by an exterilium gut, although it is less strongly expressed in rubaniform larvae. Both have early-forming, elongate, descending processes of the coracoid that serve to support the trailing intestines. Both have a greatly reduced pelvic girdle attached to a stalklike cartilaginous structure, resulting in a pelvic fin origin well posterior to the cleithral symphysis, a position that is without precedent in the family Ophidiidae. Both of these larval types also strongly display an anterior to posterior developmental sequence, lose the pelvic fin rays at transformation, and have extraordinarily elongate proximal radials supporting their dorsal and anal fins and modified proximal radials supporting the anterior dorsal fin rays. After examination of these larvae and reference to 5 previously described exterilium larvae and 1 previously described rubaniform larva, we conclude that they belong to Lamprogrammus (three species) and Brotulotaenia (four species), respectively. The most recent classification of the Ophidiidae places Brotulotaenia in the monotypic subfamily Brotulotaeniinae, and Lamprogrammus in the subfamily Neobythitinae along with 37 other genera. The latter subfamily is an unwieldy assemblage for which monophyly has never been established. Ontogenetic evidence suggests a closer relationship between Brotulotaenia and Lamprogrammus, and the most economical reorganization of the ophidiids would involve incorporating the latter genus into the Brotulotaeniinae.

Stage-specific spatial and temporal variability in the diets of larval winter flounder (Pseudopleuronectes americanus) in a northeastern U.S. estuarine nursery

Collections of winter flounder (Pseudopleuronectes americanus) larvae were made biweekly from March to May in 1999 and 2000 in the Navesink River-Sandy Hook Bay estuarine system, New Jersey, to determine stage-specific spatial and temporal variability in diets. Relatively high percentages of larvae with empty guts were found at low water temperatures. Percentages of empty guts did not differ by larval stage (preflexion and postflexion) or region of collection (river and bay). There was high intraregional variability in percentages of larvae with empty guts. Nauplii, invertebrate eggs, and polychaete larvae were dominant prey items followed by tintinnids, bivalve and gastropod veligers, and diatoms. Ontogenetic dietary shifts were evident in both years. Preflexion winter flounder largely consumed nauplii, invertebrate eggs, and tintinnids; postflexion winter flounder consumed the largest prey (polychaete larvae) but also retained small prey items in their diets. Water temperature significantly affected the percentages of larvae feeding on nauplii (p<0.05) and tintinnids (p<0.08) in 2000. Region of collection was not significantly related to diets because of high intraregional variability. Fine scale spatial (within regions, stations were approximately 3 km apart) and temporal (weeks) dietary variation of larval winter flounder could result in accompanying variation in development, growth stage duration, and survival.