Design and Implementation of a Fishery-Independent Shallow Water Trawl Survey for Maryland’s Portion of Chesapeake Bay Brandon Muffley and Alexei Sharov MD Dept. of Natural Resources, Fisheries Service Annapolis, MD

Design and Implementation of a Fishery-Independent Shallow Water Trawl Survey for Maryland’s Portion of Chesapeake Bay Brandon Muffley and Alexei Sharov MD Dept. of Natural Resources, Fisheries Service Annapolis, MD

Background Why needed ? Why needed ? – Chesapeake 2000 commitment to multispecies approaches – Past/current studies lack spatial and temporal coverage needed – Few studies incorporate shoal (shallow) areas – Wide range of information gained on a variety of economically & ecologically important species ChesFIMS survey ChesFIMS survey  Broad scale survey – mid-water trawls in mainstem of C. B.  Shoal survey – bottom trawl in shallow waters of MD C. B.

Solomons Shoal Survey Design Stratified random design Proportional station allocation Trawl design from MD DNR crab survey Surveys conducted in four mid-Bay strata, chosen for compatibility with broad scale efforts, and with existing surveys Strata 108 Stations 3 Sampling Periods 6 minute trawls S1 S2 S3 S4 Solomons

Shoal Survey Design (con.t) Stratified random design Proportional station allocation based on variance estimates Surveys conducted in nine mid & upper Bay strata, chosen for compatibility with broad scale efforts, and with existing surveys Strata 120 Stations 3 Sampling Periods 6 minute trawls S5 S6 S7 S8 S9 Annapolis

Data Collection Biological Information Species ID Length (TL) Weight Sex (blue crab) Gut content Water Quality Temperature DO Salinity Depth Secchi Misc. Information Tide State Bottom Substrate Boat Speed/RPM Position Coordinates Air Temp.

Summary Statistics 2001 MayJulySeptemberTotal # of Trawls # of Fish Total Weight (kg) # of Species MayJulySeptemberTotal # of Trawls # of Fish Total Weight (kg) # of Species

Species Caught American Eel Northern Searobin Atlantic SilversideOyster Toadfish Bay AnchovyPigfish Blackcheek TonguefishSilver Perch Blue CrabSkilletfish CroakerSpot HarvestfishSpotted Seatrout HogchokerStriped Bass Horseshoe CrabSummer Flounder LizardfishWeakfish Naked GobyWhite Perch Northern KingfishWindowpane Flounder Northern PipefishWinter Flounder Northern Puffer July 2002

Yearly Distribution of Abundance 2001 Total N Solomons 2002 Solomons

Yearly Distribution of Biomass 2001 Total g Solomons 2002 Solomons Total g

Seasonal Distribution of Biomass Total g May 2001 Solomons Solomons July 2001 Total g

Overall Catch Tow -1 by Species July 2001September 2001 Bay AnchovyBlue CrabWhite Perch CroakerSpotStriped Bass HogchokerSummer FlounderWeakfish LizardfishN. KingfishOther

Overall Biomass Tow –1 by Species July 2001September 2001 Bay AnchovyBlue CrabWhite Perch CroakerSpotStriped Bass HogchokerSummer FlounderWeakfish LizardfishN. KingfishOther

Abundance Trends Tangier Sound – Blue Crab MD DNR crab trawl surveyChesFIMS shoal survey Fixed stations * Stratified random stations Few stations * Numerous stations 16’ semiballoon otter trawl * 16’ semiballoon otter trawl 6 minute tows * 6 minute tows 5 different strata sampled by both surveys

Biological Characteristics Mean Length (mm) May 67.2 Size and size-at-age Growth rates Habitat Preferences/Associations (adults & juveniles) Recruitment Bay Anchovy * For a number of species

Biological Characteristics Mean Length (mm) May 67.2 July 43.9 Size and size-at-age Growth rates Habitat Preferences/Associations (adults & juveniles) Recruitment Bay Anchovy * For a number of species

Biological Characteristics Mean Length (mm) May 67.2 July 43.9 Sept 48.1 Size and size-at-age Growth rates Habitat Preferences/Associations (adults & juveniles) Recruitment Bay Anchovy * For a number of species

Biological Characteristics May Mean Length (mm) 60.3 July Mean Length (mm) 95.6 Sept. Mean Length (mm) For A Number of Species: Size and size-at-age Growth rates Habitat preferences/associations (adults & juveniles) Recruitment Blue Crab

Biological Characteristics Size and size-at-age Growth rates Mean Length (mm) May 60.3 Habitat Preferences/Associations (adults & juveniles) Recruitment Blue Crab * For a number of species

Biological Characteristics Mean Length (mm) May 60.3 July 95.6 Blue Crab Size and size-at-age Growth rates Habitat Preferences/Associations (adults & juveniles) Recruitment * For a number of species

Biological Characteristics Mean Length (mm) May 60.3 July 95.6 Sept Size and size-at-age Growth rates Habitat Preferences/Associations (adults & juveniles) Recruitment Blue Crab * For a number of species

Species Diversity By Strata Species Diversity vs. Species Richness September

Species Diversity By Season Species Diversity vs. Species Richness All

Species Diversity By Year Species Diversity vs. Species Richness July 01 &

Gear Comparison Study Deep Stations (8m) Shallow Stations (4m) Day TrawlsNight TrawlsOverall mean Catch tow Why needed: * Allow both surveys to be combined * Estimate small scale spatial and temporal covariation * Different sampling scheme * Different gear – fishing efficiencies

Diet Analysis Season StrataSpringSummerFallTotal Chester Eastern Bay0202 Choptank Little Choptank 0202 Tangier Pocomoke Patapsco Severn/South Calvert Cliffs Season Total Species Collected Croaker Spot Weakfish Hogchoker Striped bass White perch Northern Kingfish A. Silverside Trophic Linkages Predator – prey Multispecies models Bioenergetic models

Sample Diets  Gut contents flushed, sample split, taxa identified, weighed and counted Organic Matter Polychaete Annelid Nematode Flatworm Nemertean Gnathostomulid Tube Worm Unidentified Worm Nudibranch Insect Egg Unidentified Insect Larvae Unidentified Insect Chironomidae Diptera Tunicate Amphipod Copepod Egg Copepod Grass Shrimp Skeleton Shrimp Mysid Cumacean Isopod Gastropod Egg Gastropod Barnacle Mussel Razor Clam Unidentified Bivalve Unidentified Egg Blue Crab Unidentified Crab Clupeid Egg Unidentified Fish Egg Fish Fish Part Unidentified Percent Weight (% W) Prey Item (from Miller et. al. 2001) Striped Bass - Upper Bay (n = 24 )

Summary Information Gained: Survey design and implementation CPUE and Biomass estimates Species abundance and distribution Life history characteristics (i.e. growth and habitat use) Species diversity and richness Recruitment Trophic linkages – gut analysis Time series of abundance  Management Implications Spatially & Temporally extensive Species rich Other Areas of Interest: Water quality Trawl time Volumetric analysis / gear comparison

Acknowledgements Project funded by CBSAC through NOAA CB Office Nate Herman Tom Miller Jon Volstad Phil Jones Dale Weinrich Paul Genovese Harry Rickabaugh Keith Witeford Mark Matsche Tony Jarzynski Jim Mower Bob Sadzinski Marek Topolski Harley Speir Harry Hornick Butch Webb Bruce Pyle Jim Thompson Kinte Thompson Kevin Donaldson Bennie Williams Jen Ball Matapeake interns