Alewife Population Assessment and Aquaculture
|Matthew DiMaggio||UNH - Department of Biological Sciences||Postdoctoral Student/Researcher|
|David Berlinsky||UNH - Department of Biological Sciences||Principal Investigator|
|Michael Bailey||U.S. Fish and Wildlife Service||Associate Investigator|
|Kevin Sullivan||N.H. Fish and Game Department||Associate Investigator|
|Ken La Valley||UNH - Cooperative Extension||Associate Investigator|
|Erik Chapman||N.H. Sea Grant||Associate Investigator|
|John Whalen||Harmon Brook Farm||Industry Partner|
Together with smelt, river herring (alewives and blueback herring) comprise the most dominant anadromous species in the Great Bay estuary system and support limited fisheries. Due to coast-wide declines in river herring populations, the Atlantic states Marine Fisheries Commission’s (ASMFC) Amendment 2 to the Interstate Fisheries Management Plan for shad and river herring calls for states to close recreational and commercial river herring fisheries, with an exception for those that can demonstrate sustainable fisheries. Currently, river herring populations in New Hampshire are monitored by spawning stock returns in fish ladders on four of the seven major rivers in the estuary. Many questions regarding the efficacy of this evaluation method must be addressed, however, to determine its value in estimating annual recruitment to the fishery. In this proposal, we outline a project for collaborative research with 2 goals aimed at alewife conservation. We will: 1) examine the accuracy of river herring population assessment methods currently used in the Great Bay Estuary and 2) develop methods for alewife aquaculture for both stock enhancement and as a marine baitfish.
N.H. Sea Grant research indicates alewives may not be able to easily ascend fish ladders to spawn in N.H. rivers
Alewives are experiencing population declines throughout their range in New England waters. NHSG-funded researchers conducted tagging studies on four N.H. rivers to determine if fish ladders act as a barrier to upstream migration, possibly impacting their ability to spawn. Data results compiled in 2014 indicated that alewives do not always ascend fish ladders continuously during the spawning season, but instead may make several attempts or may cease trying. This information helps resource managers to better understand the challenges posed by fish ladders to migrating fish populations, thus improving their ability to manage the fishery.
Two videos inform and engage the public about N.H. Sea Grant research
N.H. Sea Grant produced two videos in 2013 about research projects focused on microplastics on N.H. beaches and alewife populations in coastal rivers. Both research projects were funded by NHSG. The videos were shared on social media and one was uploaded to the research page of the NHSG website, allowing the description of the research to evolve into a “living document” and gain a longer shelf-life in the news. Videos serve as a companion piece to written news stories about the research, engaging audiences in a more effective manner and encouraging volunteer participation in the research when possible, as was the case with the microplastics project.
Protocols Developed for Alewife Culture Lead to Direct Economic Benefits for Business
RELEVANCE: Smelt, alewives and blueback herring comprise the most dominant anadromous species in the Great Bay Estuary and support limited fisheries. However, recent coastwide declines in their populations are causing concern. Producing alewives via aquaculture could aid in both stock enhancement and marine baitfish supply, taking some pressure off the wild populations to ensure their sustainability.
RESPONSE: NHSG-funded researchers developed protocols in 2012 for alewife broodstock spawning, larviculture and juvenile rearing, including the establishment of salinity tolerances for larval and juvenile alewives. Researchers demonstrated the ability to successfully mass-produce thousands of young alewives in an aquaculture setting.
RESULTS: Harmon Brook Farm in Caanan, Maine, is using these protocols to culture alewives for marine baitfish purposes. This company has benefited financially from the production and sale of alewives based on these protocols and they plan to increase production in the coming years.
RECAP: NHSG-funded researchers developed alewife aquaculture protocols that are being used in a marine baitfish supply business, providing direct economic benefits.
Researchers Developed Protocols Resulting in First Mass-production of Juvenile Alewives in Captivity
Smelt, alewives and blueback herring comprise the most dominant anadromous species in the Great Bay Estuary and support limited fisheries. Recent coastwide declines in their populations are causing resource managers to seek ways of ensuring their populations are sustainable. Stock enhancement may be a viable option to achieve that goal. To that end, NHSG-funded researchers developed protocols in 2012 for alewife broodstock spawning, larviculture and juvenile rearing, resulting in the production of thousands of juveniles in a lab setting. This research is the first documented example of mass-producing juvenile alewives in captivity. These aquaculture protocols will enable resource managers and individuals interested in marine baitfish to supply alewives for economic and ecological benefit.
Studies Indicate Larval Alewives are Tolerant of Full-strength Seawater while Raised in Captivity
Alewife populations have experienced recent coastwide declines, causing resource managers to seek ways to ensure their sustainability. Stock enhancement from lab-raised broodstock may prove beneficial to meet that goal. During the development of aquaculture protocols for raising alewives, researchers conducted experiments in 2012 to establish salinity tolerances for larval and juvenile alewives. Their results indicated that larval alewives (about 45 days post-hatch) are tolerant of full-strength seawater. These results will provide more accurate information for aquaculturists to successfully raise alewives for stock enhancement and marine baitfish supply.
Tagging Studies Help Improve Alewife Population Estimates in N.H. Rivers
Alewife populations in N.H. are currently monitored by spawning stock returns in fish ladders on four rivers leading into Great Bay. In light of recent coastwide declines in alewife populations, it is essential to accurately monitor and estimate their populations and recruitment to the fishery to ensure sustainability. With funding provided by NHSG, researchers conducted preliminary stock assessment monitoring in 2012 on alewives in those four rivers to determine if current monitoring efforts are accurate. Fish were captured below the river dams, tagged and returned below the dams. Recaptures ranged from 0% - 71% covering 11 tagging events total. The results of these and other tagging studies will enable researchers to improve alewife population estimates, thus providing more accurate information for resource managers seeking to ensure sustainable fish stocks.
Available from the National Sea Grant Library (use NHU number to search) or NH Sea Grant
- DiMaggio, M.A., H.J. Pine, L.W. Kenter and D. Berlinsky. Spawning, larviculture, and salinity tolerance of alewives and blueback herring in captivity. North American Journal of Aquaculture 77(3):302-311, July 2015.
- Berlinsky, D.L., T.S. Breton, J. Walsh and A.I. Kovach. Peritoneal pigmentation in purebred and hybrid river herring. Transactions of the American Fisheries Society 144(4):717-723, July 2015.
- Berlinsky, D., M. Watson, M. DiMaggio and T. Breton (2016). The use of tricaine methanesulfonate, clove oil, metomidate and 2-phenoxyethanol for anesthesia induction in alewives. North American Journal of Aquaculture 78(1):84-91, January 2016.
- Watson, M. (2015). The use of tricaine methanesulfonate, clove oil, metomidate, and 2-phenoxyethanol for anesthesia induction in alewives (Alosa pseudoharengus). Master's thesis, University of New Hampshire.
- N.H. Sea Grant alewife research (2013) (video). See N.H. Sea Grant's YouTube channel.