The survival of diadromous fish, like river herring and the American eel, depends on their fascinating adaptation of migrating between marine and freshwater habitats to complete their life history. These fish not only face a range of threats in marine waters, but must ascend coastal rivers in the spring where they are vulnerable to overharvest by humans, predation, and the effects of habitat alteration. An appreciation for the importance of the spring fish runs is steeped in our coastal culture and has guided the development of management practices and regulations to protect these public resources. Diadromous fishes are presently managed in Massachusetts cooperatively by MarineFisheries and MassWildlife working with local municipalities and other states through the Atlantic States Marine Fisheries Commission (ASMFC).
Seventeen species of diadromous fishes are known to occur in Massachusetts. River herring are best known because of their widespread occurrence, spectacular spawning runs, and high value during former times of abundance. This group includes two closely related species, the alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis). The former is the most abundant anadromous fish in Massachusetts. However, the populations and fisheries of both species have been managed together because their appearance, life cycles, and time of migration are very similar. Other well known anadromous fish include striped bass (Morone saxatilis), American shad (Alosa sapidissima), rainbow smelt (Osmerus mordax), and white perch (Morone americana). The Atlantic (Acipenser oxyrhynchus) and shortnose (Acipenser brevirostrum) sturgeons are lesser known anadromous species because they are rarely encountered by the public, yet require the state's attention as Federally listed species under the Endangered Species Act. The American eel (Anguilla rostrata) is the only catadromous fish in North America. Diadromous fishes of Massachusetts were once so abundant that they supported important subsistence and commercial fisheries. Presently, only striped bass supports valuable commercial and recreational fisheries, while minor and mainly recreational harvest continues for shad, smelt, and eel. Despite their declining importance in fisheries, diadromous species are considered vital to marine and freshwater food webs as prey for a wide range of fish and wildlife species.
Historically, sea-run fish were managed by towns and cities in Massachusetts due to their importance in local economies and the practicality of local stewardship. However, late in the 19th century, the privatization of fish runs and waterways contributed to widespread declines. The early 20th century brought rising public concern over the status of river herring in particular, which resulted in the creation of the MarineFisheries Fishway Crew in 1934 and the MGL Chapter 130 laws ( link ).These laws gave the Director of MarineFisheries broad authority to provide passage for sea-run fish and to regulate harvest of sea-run fish while coordinating with municipalities and MassWildlife. This model for managing these fish continues today with the essential feature of working with property owners and municipalities to manage over 100 river herring runs in Massachusetts. However, the recent sharp population declines have prompted a state-wide harvest and possession ban on river herring since 2006.
The mission of MarineFisheries as it relates to diadromous fish is to restore and sustain populations and habitats, allowing these natural resources to benefit the Commonwealth through reasonable harvest and ecological contributions. To meet this goal, MarineFisheries maintains two projects that focus on diadromous fish: Diadromous Fish Biology and Management and Diadromous Fish Passage and Habitat Restoration.
The Diadromous Fish Biology and Management Project assesses and monitors diadromous fish populations in Massachusetts. This project not only maintains advanced-technology counting stations to annually record river herring spawning run abundance in each major coastal drainage area, but also conducts biological monitoring to record species, size and age composition, and sex ratio data. This project conducts similar monitoring projects for rainbow smelt and American eel populations, and represents the Commonwealth on ASMFC technical committees and management boards for striped bass, river herring, shad, eel, and sturgeon. We presently have cooperative stocking efforts with smelt and shad to restore fish populations under carefully monitored study designs. These efforts release juvenile fish, marked with oxytetracycline, an internal chemical tag that can be detected when fish are recaptured as adults. An assessment of the stocking and recapture proportions provides valuable information on stocking contributions and population recruitment. The project is fully engaged with public outreach related to the fish runs and respond to numerous requests for technical information, educational assistance, and data summaries from our ongoing monitoring.
The Diadromous Fish Passage and Habitat Restoration Project oversees the Fishway Crew, which was created almost 80 years ago. Through this project, we provide technical assistance to maintain and rebuild small fishways and assist with the design and review of larger fishway projects. For the latter, we work with the hydraulic engineers of the US Fish and Wildlife Service to design fishways. The Fishway Crew is well-equipped with a stocking truck, a mini-excavator, and a carpentry and welding shop in Sandwich. Our fish passage work has evolved in recent years to include the construction of innovative eel passageways, stream channel improvements, and dam removal projects. Our restoration efforts depend heavily on cooperative efforts with private, state, local, and federal partners. We have decades-old relationships with herring wardens in many coastal towns to keep river herring run passage open and viable. The project also assists restoration by transferring river herring from donor runs to restoration sites following our stocking guidelines ( link ), and conducts river herring habitat assessments to guide restoration decisions and seek improvements for identified water quality impairments ( link file size 1MB ).
MarineFisheries has demonstrated leadership and success in keeping the gates open for the ancient migrations of diadromous fishes in Massachusetts. The landscape has changed dramatically since this remarkable life history evolved. Across the ranges of these species, we see the influences from climate change, natural and fishing mortality, and habitat alteration remaining as significant challenges in the future. However, we are optimistic that habitat and population restoration can be achieved in Massachusetts through improvements in structural fishways, barrier removals, site specific water quality remediation, and successful inter-jurisdictional management practices.