Atlantic menhaden (Brevoortia tyrannus) support the largest fishery by volume on the United States East Coast, while also playing an important role as a forage species. Managers’ and stakeholders’ increasing concerns about the impact of Atlantic menhaden harvest on ecosystem processes led to an evolution in the assessment and management of this species from a purely single-species approach to an ecosystem approach. The first coastwide stock assessment of Atlantic menhaden for management used a single-species virtual population analysis (VPA). Subsequent assessments used a forward projecting statistical catch-at-age framework that incorporated estimates of predation mortality from a multispecies VPA while analytical efforts continued toward the development of ecosystem models and explicit ecological reference points (ERPs) for Atlantic menhaden. As an interim step while ecosystem models were being developed, a series of ad hoc measures to preserve Atlantic menhaden biomass for predators were used by managers. In August 2020, the Atlantic States Marine Fisheries Commission formally adopted an ecological modeling framework as a tool to set reference points and harvest limits for the Atlantic menhaden that considers their role as a forage fish. This is the first example of a quantitative ecosystem approach to setting reference points on the United States Atlantic Coast and it represents a significant advance for forage fish management. This case study reviews the history of Atlantic menhaden stock assessments and management, outlines the progress on the current implementation of ERPs for this species, and highlights future research and management needs to improve and expand ecosystem-based fisheries management.

The Atlantic Menhaden Brevoortia tyrannus is a clupeid that plays a critical role in the marine food web and supports one of the largest fisheries on the U.S. East Coast. Along with a decrease in overall numbers and spawning stock biomass, recruitment levels have remained low since the 1990s. Atlantic Menhaden use numerous estuaries along the Atlantic coast for juvenile development before recruiting to the adult population, but the contribution of each of these nursery grounds is currently unknown. Chesapeake Bay is thought to contribute 70% of the total recruits, although this estimate is over 20 years old and predates current low recruitment levels. We investigated the potential of trace element (Li, Mg, Mn, Rb, Sr, Y, Ba, and Pb) and stable isotope ratio (δ13C and δ18O) signatures in otoliths to distinguish among Atlantic Menhaden collected from various nursery grounds along the U.S. Atlantic coast (Connecticut to South Carolina) during 2009–2011. Juveniles were classified to four regional nursery areas with nearly 90% accuracy. Due to significant interannual variation in the chemical signatures, our attempts to classify juveniles from adjacent year‐classes or combined year‐classes resulted in lower accuracy. However, this study provides a 3‐year library of geochemical fingerprints for assigning adults to their regions of origin. This research builds the foundation for a comprehensive estimate of Atlantic Menhaden recruitment rates from each of the major nursery areas along the U.S. Atlantic coast for 2009–2011.Received May 28, 2014; accepted September 16, 2014

The Atlantic Menhaden Brevoortia tyrannus is a coastal‐spawning, estuarine‐dependent clupeid that has economic and environmental value along the U.S. East Coast. Atlantic Menhaden spawn offshore and rely on circulation patterns in the ocean to deliver larvae to multiple estuarine nursery grounds for juvenile development before recruiting to the adult stock. Historical estimates of the Atlantic Menhaden nursery contribution by each of the major nurseries along the coast indicate that the Chesapeake Bay produces 69% of the recruits to the adult stock; yet, these estimates are over 20 years old and have never been quantitatively validated. We used otolith chemistry for three cohorts of age‐1 Atlantic Menhaden to evaluate nursery contribution and provide updated recruitment rates for each of the nursery grounds for this species. Based on geochemical signatures and a quadratic discriminant function that assigned juveniles to their nursery grounds at nearly 90% accuracy, we classified age‐1 menhaden of unknown nursery origin collected coastwide. We found that for the 2009–2011 year‐classes, the contribution from Chesapeake Bay still dominates the proportion of age‐1 recruits, but this contribution has declined to between 16% and 65% of that earlier estimate. Nursery grounds in New England as well as those found south of Chesapeake Bay have become more significant contributors of age‐1 Atlantic Menhaden than previously expected. Received November 7, 2015; accepted January 26, 2016 Published online April 27, 2016

Consideration of the full annual cycle population dynamics can provide useful insight for conservation efforts, but collecting data needed to estimate demographic parameters is often logistically difficult. For species that breed in remote areas, monitoring is often conducted during migratory stopover or at nonbreeding sites, and the recruitment rate of new breeding adults can be difficult to estimate directly. Here, we present an integrated population model that uses mark-resight and count data to estimate survival probability, population growth rate, and recruitment rate for an Arctic-breeding shorebird of conservation concern, the red knot (Calidris canutus rufa), from data collected during spring stopover in Delaware Bay, USA, from 2005 to 2018. At this site, red knots feed primarily on the eggs of spawning horseshoe crabs (Limulus polyphemus), a legally harvested species. We used this model to estimate the relationship between horseshoe crab abundance and red knot demographics, which informed a recent revision to the framework used to establish horseshoe crab harvest regulations. Our analysis indicates that the red knot population was most likely stable from 2005 to 2018 (average λ = 1.03, 95% credible

Much is known about the life history of the Atlantic Menhaden Brevoortia tyrannus, and yet the impact of multiple nursery grounds on population structure remains a central challenge in understanding this species. Historic estimates hypothesized that the Chesapeake Bay is the predominant contributor of new recruits (age 1) to the adult stock, but no research has been done on which nursery grounds support the adult stock. In this study, we used previously established chemical signatures from juvenile otoliths to evaluate the natal origin of adult Atlantic Menhaden (ages 2-4) that correspond to the 2008-2010 year-classes. We found that, on average across ages, the northeastern, Chesapeake Bay, and southeastern nursery grounds each contribute about 30% of the recruits that persist into older age-classes and that over the 3 years of the study the proportion of nursery contributions from each nursery was relatively stable. This has repercussions for the fishery, as most fish ages 2-3 are fully mature and thus comprise the majority of the spawning biomass as well as the commercial landings in recent years. In addition to identifying regions that are essential for the persistence of this species, these results suggest that productive nurseries are related to ageand size-dependent migration as well as physical conditions in the ocean.