Northwest Atlantic redfish science priorities for managing an enigmatic species complex

Abstract

Redfish (Sebastes spp.) in the Northwest Atlantic (NWA) extend from Baffin Island in the north to the Gulf of Maine in the south. The two most abundant species are S. mentella and S. fasciatus, which are morphometrically similar and difficult to visually distinguish. Redfish are long-lived, slow-growing, late-maturing, tend to produce large year classes episodically, and have complex population structure. Intraspecific genetic groups are abundant in the NWA. They are often semi-pelagic and patchily distributed, which makes them difficult to survey. These are all characteristics that cause difficulties for stock assessment and for sustainable fisheries management. This was the focus of The Ocean Frontier Institute Northwest Atlantic Redfish Symposium in 2018. In this paper we synthesize the information known about NWA redfish. To improve the scientific basis for sustainable harvest strategies, key research recommendations involve: 1) improved biological sampling including species and ecotype; 2) develop integrated stock assessment models; 3) develop harvest strategies with management reference points that are appropriate for redfish; 4) improve fishing technology and practices to avoid capture of small non-marketable redfish and other species.

Occurrence and behavioral rhythms of the endangered Acadian redfish (Sebastes fasciatus) in the Sambro Bank (Scotian Shelf)

“…Most individuals displayed sitting or passively displacing (descending or drifting) behaviors (94.8% and 92.8% in FOV1 and FOV2, respectively; see Figure 3). Northwest Atlantic Sebastes species exhibit a semi-pelagic shoaling behavior vertically migrating to shallow depth on a diurnal bases to feed (Cadigan et al, 2022). The stomach content of S. fasciatus are mainly pelagic organisms (i.e., up to a 90% of total stomach volume) CANOCO bi-plot showing the ordination of behavioral categories, observation made during the videos (points) and the roles of the significant environmental variables (red vectors), whose length is proportional to their significance in explaining the distribution of biological data as response variables.…”

“…Also, in the northwest Atlantic, Sebastes spp. are suspected to mate on midwaters from late summer to early winter and larvae are speculated to be released in deeper waters below the intermediate cold layer during spring months (Cadigan et al, 2022).…”

Reduction in size‐at‐maturity in unprecedentedly strong cohorts of redfish (Sebastes mentella and S. fasciatus) in the Gulf of St. Lawrence and Laurentian Channel

“…Since 1993, catches have decreased substantially. For instance, 40,308 t were landed in 2018 for all NWA redfish stocks (Cadigan et al, 2022). Various stocks are present in the NWA (Figure 1), here we investigated Units 1 and 2 redfish, which correspond to the Northwest Atlantic Fisheries Organization (NAFO) Divisions 4RST and from January to May Subdivisions 3Pn4Vn, and Subdivisions 3Ps4V4Wfgj and from June to December Subdivisions 3Pn4Vn, respectively.…”

Developing a full-scale shaking codend to reduce the capture of small fish

“…fasciatus ), and are typically considered together as redfish ( Sebastes spp.) [ 6 , 7 ]. These species are slow growing, late maturing, and long-lived and thus are susceptible to overfishing [ 8 ].…”

“…In the Gulf of St. Lawrence, CA, two redfish species are commercially harvested, deepwater redfish (Sebastes mentella) and Acadian redfish (S. fasciatus), and are typically considered together as redfish (Sebastes spp.) [6,7]. These species are slow growing, late maturing, and long-lived and thus are susceptible to overfishing [8].…”