FISHES, FISH ASSEMBLAGES, AND THEIR SEASONAL 



MOVEMENTS IN THE LOWER BAY OF FUNDY 



AND PASSAMAQUODDY BAY, CANADA 



J. Stevenson Macdonald, 1 , Michael J. Dadswell, 2 

 Ralph G. Appy, 3 Gary D. Melvin, 2 and David A. Methven 4 



ABSTRACT 



Five fish assemblages, dominated by pleuronectids, cottids, gadids, clupeids, and rajids, were identified 

 from collections taken during a 5-year survey in the lower Bay of Fundy region, Canada. Individual assem- 

 blages occurred in each of estuarine, beach, pelagic, and offshore hard- and soft-bottom habitats. Species 

 and/or age-class components within assemblages varied seasonally but, in general, each assemblage was dis- 

 tinct. There was a progressive seaward displacement of these assemblages from shallow, inshore to deeper, 

 offshore habitats in winter followed by a reversal during summer. Yearly changes in species occurrence and 

 abundance during the study period were predominantly attributable to variation in ocean climate. Long-term 

 changes in abundance of two commercial species at one of the sampling sites, since a similar study there in 

 1965, appear related to population fluctuations in the Bay of Fundy and the Gulf of Maine. The beach habitat 

 apparently served as a major nursery area for juvenile gadids, pleuronectids, and clupeids. 



Although the fish fauna of the Bay of Fundy-Gulf of 

 Maine system is well documented (Bigelow and 

 Schroeder 1953; Leim and Scott 1966), few studies 

 have examined long-term spatial and temporal 

 changes or interrelationship among the fish assem- 

 blages. Previous studies in this region were con- 

 cerned with the biology and seasonal movements of a 

 single species (McCracken 1959, 1963; McKenzie 

 and Tibbo 1961; Wise 1962) or the occurrence and 

 composition of communities at a single site (Bigelow 

 and Schroeder 1939; Tyler 1971). 



Moore (1977) and Quinn (1980) have emphasized 

 the need for long-term research to establish baseline 

 information and estimates of natural variability for 

 fisheries assessments and pollution impact studies. 

 This is particularly true for inshore regions because 

 of their importance as nurseries and feeding grounds 

 (Warfel and Merriman 1944; Rauck and Zijlstra 

 1978). The increasing interest in trophic rela- 



'Department of Zoology, University of Western Ontario, London, 

 Ontario. Canada; present address: Department of Fisheries and 

 Oceans, West Vancouver Laboratory, Vancouver, British Columbia, 

 Canada V7V 1N6. 



'Fisheries and Environmental Sciences, Department of Fisheries 

 and Oceans, Biological Station, St. Andrews, New Brunswick, 

 Canada EOG 2X0. 



'Fisheries and Environmental Sciences, Department of Fisheries 

 and Oceans, Biological Station, St. Andrews, New Brunswick, 

 Canada; present address: Department of Zoology, College of 

 Biological Sciences, University of Guelph, Ontario, Canada NIG 

 2W1. 



'Fisheries and Environmental Sciences, Department of Fisheries 

 and Oceans, Biological Station, St. Andrews, New Brunswick, 

 Canada; present address: Department of Biology, Memorial Univer- 

 sity, St. John's, Newfoundland, Canada A1B 3X9. 



tionships among entire communities of fishes is 

 further reason to document movement, abundance, 

 and co-existence of fishes potentially utilizing the 

 same food resource (Richards 1963; Keast 1970; 

 Tyler 1972; Steiner 1976; Hacunda 1981). 



Long-term changes in fish assemblages have been 

 attributed to overexploitation of one or more of the 

 species within the assemblage (Brown et al. 1973; 

 Burd 1978; Sherman et al. 1981) and climatic 

 variations (Dow 1964; Sutcliffe et al. 1977). 

 However, it is usually difficult to separate natural 

 fluctuations from those caused by imbalance in com- 

 petitive and predator-prey relationships due to 

 exploitation (Cushing 1980; Daan 1980; Sissenwine 

 et al. 1982). With the view in mind of assessing these 

 long-term changes to properly assign cause and 

 effect, repetitive, in-depth studies of well-known or 

 type localities are needed. 



This study examines spatial and temporal variation 

 in fish diveristy and abundance over a 5-yr period at 

 two offshore stations within Passamaquoddy Bay, 

 one offshore station in the Bay of Fundy, and at 

 inshore and beach stations in Passamaquoddy Bay. 

 One offshore station was the same station sampled 

 by Tyler (1971) during 1965-66, allowing documen- 

 tation of changes that have occurred over the inter- 

 vening 10-15 yr. 



METHODS 



Three offshore stations in the Bay of Fundy (B) and 

 in Passamaquoddy Bay (A, C) (Fig. 1) were sampled 



Manuscript accepted August 1983. 

 FISHERY BULLETIN: VOL. 82, NO. 1, 1984. 



121 



