Cunner (Sea Perch)
Cunner as "retained bycatch" in the Lobster fishery of LFA27
Cunner, also known as sea perch, reaches maturity at 8-11cm in length and spawns in June to August in the Gulf of St. Lawrence and a little later along the Nova Scotian coast. At four years old, cunners reach 16.5cm in length. These fish can grow up to 43cm long and weigh up to 1.4kg. Cunner is a groundfish that preys on post-larvae lobster. Cunner also eats the bait from lobster traps, leaving them void of bait to attract the targeted species. As the water temperatures have increased over the last few years, so has the occurrence of cunner. Whereas they used to be a nuisance to lobster fishermen by cleaning off the bait starting in mid-June, they are now appearing earlier at the start of the season. Since 2011, CBFHA has been working with local government and stakeholder groups to allow the retention of this by-caught species to be legally used as bait in the lobster fishery. Other areas, like our neighbours in the Gulf region, are allowed to retain cunner that is hauled up in the traps as bait for the industry. This can be found in their license conditions.
A pilot project was initiated in 2016 to allow retention of incidentally caught cunner. For this pilot project, lobster harvesters were allowed to retain cunner ≥ 10cm as bait for 3 seasons (2016, 2017, 2018), while CBFHA monitored cunner by-catch through at-sea sampling. The purpose was to monitor the population caught in lobster traps and produce timely, reliable, and aggregated reporting on retained and non-retained cunner. With the data entered into DFO's database, the impact of retaining cunner was evaluated based on its impact on the cunner species. Throughout the first lobster season (2016) CBFHA sampled on 98 at-sea trips over 23 recognized ports in LFA27 and 387 cunner were sampled (figure 1A). Of these cunner, only 198 were retained from 18 ports. The pilot project was extended for another five seasons (2019, 2020, 2021, 2022, 2023), therefore, catch data is still being collected by the industry and reported annually to DFO.
In 2018, the LFA27 Lobster Advisory Committee (LFA27 LAC) asked CBFHA to request DFO to make an amendment in LFA27 lobster license conditions to allow, on a permanent basis, the retention of cunner (≥ 10cm from tip of the nose to the end of the tail). The pilot project for cunner retention in lobster traps has indicated that catch per unit effort has remained stable in two years of the pilot (2017 and 2018) and that cunner of less than 10cm (minimum retention size) are rarely caught in lobster traps.
Monitoring the cunner population caught up in lobster traps has produced timely, reliable, and aggregated reporting on retained and non-retained cunner. This data was and will continue to be entered into DFO's database, providing the opportunity for the CBFHA and DFO scientists to evaluate the impact of retaining the by-catch of cunner.
When this project began there was no directed market for cunner, and the occurrence of the species had been increasing since before 2011. Fishers used to catch cunners starting in mid-June, but with changing climate patterns the fish and associated nuisances, it has increased to a season-long interaction. Currently, there are still no direct markets for cunner and since the lobster fishery is the only fishery that catches cunner incidental to fishing activities, there is no risk of cumulative fishing mortality across fisheries. Therefore, the CBFHA’s at-sea sampling should be sufficient to monitor the cunner population as it is used as a bait species.
Maturity
To determine the maturity staging of cunner, lobster technicians would retain 5-10 legal size cunner (10cm) from fishing vessels during the fishing season. Technicians procedures are:
* measure the total length (cm)
* measure the total weight (g)
* dissect the cunner to look at their gonads
* determine the stage of the gonads to find their sex maturity
