Massachusetts Division of Marine Fisheries Technical Report TR-6 THE MARINE RESOURCES OF SALEM SOUND, 1997 Bradford C. Chase, Jeffrey H. Plouff,and Wayne M. Castonguay Massachusetts Division of Marine Fisheries Department of Fisheries,Wildlife and Environmental Law Enforcement Executive Office of Environmental Affairs Commonwealth of Massachusetts chnical Report October 2002 Te Massachusetts Division of Marine Fisheries Technical Report TR-6 THE MARINE RESOURCES OF SALEM SOUND, 1997 Bradford C. Chase, Jeffrey H. Plouff,and Wayne M. Castonguay Annisquam River Marine Fisheries Station Massachusetts Division of Marine Fisheries Gloucester, Ma 01930 Massachusetts Division off Marine Fisheries Paul Diodati, Director Department of Fisheries,Wildlife and Environmental Law Enforcement Dave Peters,Commissioner Executive Office of Environmental Affairs Bob Durand, Secretary COMMONWEALTH OF MASSACHUSETTS Jane Swift, Governor OBJECTIVES 1. Assess the status of marine fishery resources and water quality in Salem Sound. The assessment targeted the following subjects at subtidal and intertidal habitats. • Finfish and major decapods. •Presence of shellfish, marine macrophytes, and other macroinvertebrates. • Basic water and nutrient chemistry (at marine and river stations). • Relationships between watershed and point-source pollution inputs to water quality. • Existing commercial and recreational fisheries. 2. Compare the results to the 1965 Salem Sound DMF study and other relevant studies. 3. Provide recommendations for protecting the marine resources of Salem Sound. View of Salem Sound from Beverly Harbor i EXECUTIVE SUMMARY INTRODUCTION FRESHWATER WATER CHEMISTRY Natural marine resources were an essential component of The freshwater tributaries running into Salem Sound are the development of the Salem Sound region, and are relatively small, and 1997 discharge was depressed by dry important today because of their cultural, aesthetic, conditions.The average contribution from all stations was commercial,and recreational value.We conducted a year- less than 100,000 m3/day. Given the low freshwater long study of the marine resources of Salem Sound in discharge and high tidal range, in most cases, freshwater 1997, focusing on the status of marine fishery resources chemistry influences were confined to river and estuarine and water quality.The study also assisted the conservation habitat. Basic water chemistry reflected conditions that interests of local and inter-agency groups, provided were supportive of aquatic life in most cases,and elevated limited comparisons to DMF studies on marine resources concentrations of nutrients were found at each freshwater in the 1960s and 1970s,and provided baseline information station. Sampling in 1997 revealed the following trends: to assist the review of large regional projects (power plant, • Infrequent violations of SB criteria for dissolved oxygen dredging and wastewater treatment plant upgrade). (< 60% saturation) were recorded, and frequent violations of the SB criteria for pH (< 6.0 pH units) MARINE WATER CHEMISTRY were found at Sawmill Brook, Manchester. Salem Sound is a relatively shallow, well-flushed embayment with minor freshwater inputs. These • High measurements of fecal coliform bacteria were conditions limit stratification,prevent the development of recorded at river stations, exceeding water quality severe dissolved oxygen depressions and appear to reduce criteria for primary recreation and contributing to the spatial influence of watershed and point source inputs degraded water quality at estuarine habitats. of nutrients. We measured basic water chemistry, fecal • Spring nitrate and orthophosphate and summer coliform and nutrients during 18 sampling trips in 1997. dissolved organic nitrogen were found at concentra- Most nutrient measurements reflected low concentrations tions that raise concerns over potential impacts to and the fluctuations expected due to seasonal aquatic resources. phytoplankton dynamics. Sampling in 1997 revealed the following trends: •Although TN concentrations in rivers were high,TN loading to Salem Sound was relatively small because of • All bottom dissolved oxygen measurements exceeded low freshwater discharge.The TN load from the five SA criteria (Mass. DEP surface water quality criteria, primary tributaries was approximately 60 mt/year in Table 3.1) for supporting aquatic life (>75% saturation). 1997. No SA or SB violations were recorded for the other basic water chemistry parameters measured. SHELLFISH SURVEY • Measurements of fecal coliform bacteria met water We surveyed 1,187 acres of intertidal habitat in Salem quality criteria for primary recreation at most stations, Sound and found that slightly more than half had potential however, many stations exceeded criteria for shellfish to support soft shell clams,of which,only 19% contained harvest. soft shell clams. High densities of soft shell clams were found in several tributaries to the Danvers River,although • Elevated surface turbidity,ammonium and orthophos- several clam flats reported as productive in 1965 were not phate were detected near the effluent outfall of the productive in 1997. Overall, the estimate of productive region’s wastewater treatment plant. soft shell clam habitat declined by 72% from the amount • The warming influence of the Salem Harbor power estimated in 1965.The accuracy of these estimates and plant cooling water discharge was detected by finding potential causes for this decline are not known.In addition elevated surface water temperature at intertidal and to soft shell clams, we observed large populations of blue subtidal sampling stations in Salem Harbor. mussel and European oyster during the survey, and incidental occurrences of quahog, surf clam, razor clam • Estimates of total nitrogen (TN) loading from outfall and American oyster. effluent (941 mt/year) were higher than river sources in 1997, however the daily load is relatively small, representing about 1% of available TN in Salem Sound on a given day. ii FISHERIES TRAWL CATCHES AT SUBTIDAL HABITAT Historically,marine fishery resources had a vital role in the Thirty-five species of fish and nine species of decapod development of culture,commerce and the communities crustaceans were caught during 168 boat trawl tows at five of the Salem Sound region. The commercial fishing subtidal habitat stations in 1997.Winter flounder, skate, industry and its relative contribution to local commerce and Atlantic cod were the top ranked fish, respectively,in has decreased dramatically since the 19th century, yet a both relative abundance and frequency of occurrence. valuable lobster fishery remains as well as modest local Sand shrimp dominated the trawl catch of decapods, and fisheries for mackerel, striped bass, sea scallop and sea rock crab and lobster were the only other decapods to urchins. Lobster landings for the region exceeded one occur in at least a third of the tows.A large majority of the million pounds first in 1978 and have fluctuated between fish catch was juveniles. Peak catches occurred in the one and two million pounds since. Lobster landings in summer and fall, and was probably most influenced by 1997 were about 1.2 million pounds with an ex-vessel warmer water temperature and young-of-the-year value of nearly four million dollars.Recreational fisheries recruitment to subtidal habitats. Overall, the catch became important to the region in the 20th century. composition appeared typical for embayments in the Gulf Catches of popular groundfish in Salem Sound are of Maine.The highest fish diversity was associated with dependent on Gulf of Maine stocks of fish that have the greater structural complexity of benthic habitats found declined since the 1965 DMF study.The winter flounder outside Marblehead Harbor (larger sediments) and fishery alone was widely renowned and supported five BeverlyCove (eelgrass), however, the highest relative rental boat liveries. Catches of winter flounder in the abundance and species richness for fish was found at the 1990s have declined sharply since the 1960s and 1970s, uniform, muddy bottom in Salem Harbor and Haste and catches of the other groundfish in the Sound have also Channel. declined. Striped bass were the top target and catch in Salem Sound in 1997 and provided excellent fishing INVERTEBRATES AND MACROPHYTES opportunities to many anglers. We also recorded the presence of macrophytes and small invertebrates that were caught incidentally at intertidal SEINE CATCHES AT INTERTIDAL HABITAT and subtidal habitats.Thirty-four species of macrophytes Twenty-three species of fish and six species of decapods were recorded at the seine and trawl stations. Red algae were caught during 136 beach seine hauls at six intertidal was the most diverse group (16 species) and brown algae habitat stations in 1997. Most of the species occurred were dominant in terms of relative abundance.A total of infrequently and in low numbers. Atlantic silverside, 22 species of Arthropods was identified in all collections, winter flounder and mummichog were the only species of which tubed amphipods, sand shrimp, mysid shrimp, to occur in at least 20% of the hauls.Atlantic silverside, rock crab, lobster, and the invasive green crab were most Atlantic menhaden, and Atlantic herring were the top common.The European oyster,green fleece (green algae), three fish in terms of numbers caught. Sand shrimp was and several species of colonial Ascidians and tunicates were the most abundantly and frequently caught decapod (90% other invasive species commonly observed.