Survey
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Coastal fish populations – do we know where the fish are? Topics to Address: • What fish are using the inshore and how are they using it? • How is our knowledge of species life histories, distribution and abundance biased by our sampling (spatially, temporally)? What are we missing? • Are there specific areas that are important as: • Spawning areas? Migratory routes? Nursery areas? • For which species do we have evidence for population structure - Can we extrapolate to other species? • Has use of inshore habitat by fish changed? Some fish remain inshore. Some are seasonal migrants - or just passing Through Some spend some life-stages inshore and others offshore Annual monitoring • DFO research vessel survey has annual coverage since 1970, but misses much of the inshore – too rough to trawl. • Detailed biological sampling, but high variability in estimates for benthic fish which go under the net. • Changes in relative inshore abundance are not detected. ITQ Survey • About 184 stations sampled annually. • Good sampling off SW Nova Scotia. • No inshore stations between St. Margarets Bay and Shelburne. • Catch includes most fish encountered no space below footrope, but less detail recorded in data for most species 8° 66° 64° Cod from ITQ • • • • Most cod caught in the Bay of Fundy Inshore catches highest off Cape Sable In eastern 4X cod are must abundant inshore Age 0 and 1 catch highest inshore Winter flounder from ITQ • Found only in depths <50fm • Few in St. Margarets Bay Dogfish from ITQ Caught all around Nova Scotia. Most abundant in Bay of Fundy and mid-depths on the Scotian Shelf. 4VsW Sentinel • Covers eastern Scotian Shelf, with good inshore sampling. • Catch restricted to fish that take a commercial size hook • Limited biological sampling for most species Cod • Caught throughout the inshore area • Catches are largest inshore • Cod dominate the catch Other species: Several species combined - same weight scale as cod Combined weight less than cod at most locations Most fish are caught off Halifax and near Chedabucto Bay Fishery Data • Landing coordinates are only available since about 1996 for fixed gear, 1991 for otter trawl. • Prior to 1960, landings are recorded by county - primarily coastal hook and line, which gives a coarse resolution on location. • Coastal fisheries were scattered along the entire shore. • The major fisheries along the shore for cod haddock and pollock were Cape Sable-Shelburne, St. Margarets Bay Halifax, around Chedabucto Bay and Sydney Bight. Longline landings in summer 2003 • Landings data provide some information on species composition inshore. • Cod, haddock and halibut caught inshore, with small amounts of other species. • Currently two areas with active fisheries. Otter trawl landings - 1991 • Broad area covered, but limited coastal fishing • Little observer coverage, so limited information on noncommercial species Otter trawl landings - 2002 • Very little coastal fishing outside of the Bay of Fundy in recent years • Little fishing east of Halifax due to management restrictions Otter trawl species composition in 1992 Inshore catches were primarily winter flounder and cod. Very little observer coverage, so only data on commercial species. Inshore pollock catches • Inshore fishery was extensive • Gilllnet caught 000's tonnes annually in fall. • Pollock caught in mackerel traps in St. Margarets Bay (4060cm); large pollock also caught in trapnets. • Little inshore catch of pollock now. 30 pollock lengths (cm) 25 20 15 10 5 0 73 79 82 85 88 91 94 97 100 103 106 109 115 35000 Cod fishery 5Y 4Xu 30000 4Xs 4Xr 4Xq 25000 4Xp 4Xo 4Xn 20000 4Xm 15000 10000 5000 0 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998 • Prior to the arrival of otter trawlers in the early 1960’s, inshore hook and line was the bulk of the fishery. • Inshore catches (4Xmo) remained dominant until the 1990’s. Haddock fishery • Very little inshore haddock fishery now • Handline fishery was active around Cape Sable until late 1990’s • A tagging study in the 1930’s used fish caught in the haddock trap fishery, which was active in a number of sites from St. Marys Bay to Ingonish (May-July). • Haddock could be seen on the bottom in 2 fm. of water. Haddock fishing was primarily coastal in the early 20th century In some areas this was seasonal while others (Passamaquoddy Bay) it was year-round Mackerel Landings by Area • Mackerel migrate through inshore Nova Scotia • There is an active fishery in some areas, and recreational fishing is widespread 98 8 613 4Ra 4Rb= 2 372 1 4To 11 400 C 4Tu= 1 4Tn= 4Tm 220 4Tl= 4 297 4Rd 4Tg= 1 966 4Xo= 1 503 3Lj= 4Vu= 2 Ï-P-É / PEI 4Vn= 9 4Th= 208 4Wd= 47 se cos 4Wk= É 2 4Wh= elle 2 v 4Xm= u o 1 N 1 854 B 9 3Lb= 29 3Pn= 21 tia Sco a ov /N 4Xr= 4Xq= 15 12 4Tf= 976 266 4Tj Terre-Neuve / Newfoundland 9 534 4 917 3Ki= 1 572 3La= 4Rc= 677 NouveauBrunswick / New Brunswick 3Kd 3Kh D 10 3Lq= 13 Tuna show up in coastal areas where they feed on mackerel and herring Dogfish landings The main coastal hook and line fishery recently is for dogfish Dogfish are not a recent arrival in inshore – In 1930 they were abundant around Campobello and reportedly restricted fishing for hake until mid-November Main remaining fishing areas are around Cape Sable and off Halifax with others important in past HERRING SPAWNING LOCATIONS 47 46 d an nt n e ter as pon E m , on g Co t e r in e B awn p Ca Sp ks tal ore s an a Sh o B C th lf u he nent o S S o n tia omp o C Sc re ning o h w fs Of Spa 45 SW Nova Spawning Component 44 43 42 G 41 70 in awn p S nk s Ba e g r eo 69 68 67 nent o p m g Co 66 65 64 63 62 61 60 59 Gillnet catches for 2005 Herring gillnet landings 2005 47° Catch dates from Jun-09-05 to Oct-08-05 Total Catch - 3490 t Total No. slips - 513 Plotted catch - 3489 t Catches w/o location - 0 t 46° 45° 44° Gillnet Catch t 10 50 100 250 0 • Few active inshore fishing grounds. • Herring and herring eggs are a major food source for many species when available. • Large winter fishery in Chedabucto Bay in past. Cod spawning • Cod spawn in coastal Nova Scotia in fall. Halifax Harbour spawning was studied extensively in 10-15 m of water. Tagging studies have helped uncover movement patterns and determine stock structure Returns from South Shore cod tagging studies – limited movement, with most remaining inshore Some areas had more inshore-offshore mixing Pollock Tagging • Small pollock (20-35 cm) tagged in Chedabucto Bay Halifax hrbr and Cape Sable. • 1st year returns all local – subsequent years they dispersed to offshore areas. 48° 47° 46° 45° 44° 43° 42° Juvenile cod mainly in shallow coastal waters – lots of things to hide in and under Juvenile distribution • Can be difficult to study from standard DFO data collection – small cod go under the net. • Haddock are offshore • Cod, pollock and white hake are inshore • Small cod prefer eelgrass (lab studies) as do white hake and have higher survival in this habitat (St. Margarets Bay) • Beach seining in the 1930’s found cod (3-10cm) in many locations around Nova Scotia. Less success in 2000 Black rock beach at low tide in eel grass. • Pollock dispersed through coastal habitats, but prefer areas with cover. Stock Structure • Little known for most species • Some similarities in growth patterns and tagging study results for cod haddock and pollock – perhaps stock structure can be inferred for species with similar life history? Conclusions: • Less fish inshore than in past – inshore fisheries very poor. • Little annual monitoring inshore – some areas impossible to sample with standard survey procedures. • Inshore biomass unknown. • Surveys which cover inshore collect limited biological data. • Important Areas? • Around Cape Sable – cod spawning, juvenile fish, diverse catch • Around Halifax – cod and herring spawning, has been productive fishery. • Sydney Bight • Mouth of Chedabucto Bay Some fish remain inshore throughout their lifespan • Some fish are seasonal migrants – Some species come inshore to feed (Dogfish, large pelagics ) – Some come inshore to spawn (Herring, lumpfish) – Some spend time in coastal areas for unknown reasons (overwintering herring in Chedebucto or off Hfx) • Some spend life-stages inshore • Coastal area are productive, and have structure for hiding. Mackerel feed and migrate through Cod, pollock, winter flounder spawn Juvenile cod, wh. Hake in eel grass; pollock in rockweed, eelgrass etc. Coastal fisheries have declined Juveniles are more difficult to locate than in past