Fisheries & Conservation Science Group

Finfish Fisheries

Our scientific programme on bass and other fish: a personal perspective by Michel Kaiser

We are currently involving recreational and commercial fishers in improving data collection methods on the spatial-temporal distribution of fishing effort, CPUE (catch per unit effort) data, key areas for species conservation and economic information of their activities (through questionnaires, on-board observations, novel tools for data collection). We aim to provide the commercial fishing industry and recreational anglers with valuable results essential for sustainable use of the finfish resources.

Please get involved and contact:

Recreational Sea Anglers

To ensure a sustainable future for bass we need anglers to help the fisheries team understand the recreational bass fishery. Our findings will be reported to the Welsh Government, who is mandated to manage bass stocks to maximise long term benefit to all stakeholders. This mandate will be exercised in consideration of the contribution of angling to the Welsh economy as recognised in the Wales Fisheries Strategy of 2008 and the Future Direction and Strategic Action Plan of 2013.

The project is backed by the Welsh Federation of Sea Anglers and is funded with public money. The input of as many anglers as possible is vital to maintain due recognition of the recreational angling sector in Wales and to ensure that your interests are represented from a foundation of sound scientific data.

If you have any questions concerning this aspect of the project, then please review this response, previously posted on worldseafishing.com, Q & A’s appear after Mike’s text.

How to get involved:

  • By sharing any historical catch diaries you or your club may have
  • Collecting biological samples (scales/fins/guts/gonads) from bass you keep for the table

Please get involved and contact:

Dr Giulia Cambiè:
g.cambie@bangor.ac.uk
01248 382615

All fishers

Sampling kits for biological data collection have been given to commercial and recreational inshore fishers. The kits contain:

  • x 1 GPS data logger to have an insight into the fishing effort distribution and capture locations
  • x 20 envelopes to collect scales from each bass caught. The analysis of the scales will be useful for a spatial management approach to the fisheries.
  • x 20 bags to collect guts and gonads from each bass caught. Male/female proportion and the stage of maturity by area and season will give useful indicators for fisheries management.
  • x 20 tubes containing ethanol (100%) to collect fin clips for genetic analysis (in collaboration with the Aquatrace project)
  • x 1 plastic knife (for scales), x 1 tape measure (to measure the total length of each bass), x 1 pencil, x 1 logsheet to record the total capture for each haul
  • Complete instruction guidance for the data collection. Please click here for a PDF of the instructions.

Please get involved and contact:

Dr Giulia Cambiè:
g.cambie@bangor.ac.uk
01248 382615

Fish merchants


Images: Cutting open a sea bass to take the guts and gonads & measuring bass and taking scale samples.

To assess the maturity of sea bass and to look at the male: female ratio we need samples of bass gonads. We have encountered difficulties obtaining the guts and gonads of sea bass from fishers as bass are often sold whole. Therefore we have started going to fish merchants, where the bass are gutted for customers, to collect as many samples as possible. Many thanks to the merchants we have worked with so far; Chris Davies from Welsh Seafood in Milford Haven docks, Owen Davies from Channel Fish in Burry Port, Debbie & Paul from Swansea Fish, Tucker's and Coakley Greene in Swansea Market, Gill fromGill's Plaicein Tywyn and Mermaids Seafoods in Llandudno.

If you are a fish merchant and would like to get involved then please get in touch. We will not interfere with any work, we just need a corner where we can measure bass, take a small fin clip, a few scales and where possible take gut and gonad samples.

Contact Giulia Cambiè:

g.cambie@bangor.ac.uk
01248 382615

Recruitment index


Image: Learning the art or beach seine netting – from left to right Harriet Salomonsen, John Lancaster & Giulia Cambiè

We began our sampling to find the O group age class of sea bass. This will enable us to assess the abundance of bass recruiting to the area and to start developing a recruitment index. This will help us to understand the state of the stock and to gain insight into recruitment into the bass fishery.  

Thanks to the help of John Lancaster of Swansea University we have been learning how to use a seine net to catch these tiny juveniles.

Our full sampling programme began at the end of July. Few recruits from this year’s breeding season arrived on South Wales.

Images: Left. A different technique for sampling in the tide off a slip way – John Lancaster & Giulia Cambiè. Right. 0-group sea bass caught in Swansea Bay

 

D. labrax is the target species of both commercial and recreational fisheries.

Commercial fisheries

The official total bass landings in England and Wales from Sub-areas IV and VII rose from 106 t in 1985 to 680 t in 1999 and have averaged around 500 t since then. However most of the bass landed into the UK is taken by small inshore vessels in a mixed gear fishery and does not go through major ports: these figures are therefore underestimates. A combination of the official UK statistics and landings derived from a voluntary log-book scheme run by CEFAS produced best estimates, which suggest that landings remained around 600 t between 1985 and 1992, rising rapidly to 2200 t in 1994 (as the strong 1989 year class recruited), and then fluctuated between 1050 and 1900 t (mean approx. 1500 t) until 2005 (ICES, 2004; ICES, 2008). During this period, bass landings into England and Wales were mainly from netting and line métiers.

The main fishing gears used by the inshore UK fishing vessels are drift nets, gill nets, longline, angling, and rod and line. The mean value of catches estimated in 2002 for all nets was 16 kg day-1 and 10.3 kg day-1 for all lines (ICES, 2004).

From 1995, up to seven pairs of midwater trawlers targeted bass. Catch rates in the winter pair-trawl fishery in 2002/03 ranged from 64 to 455 kg per pair-day, and averaged 19.1 kg per hour fished (ICES, 2008).

Recreational fishers

Marine recreational fisheries play an essential role in exploiting sea bass and it is also a crucial component of the local economy in the UK. Evidence suggests that the estimated annual catch of sea bass by sport-anglers has an order of magnitude similar to that recorded from the commercial fishery. Some 24 500 sea-anglers fished regularly for bass in the UK in 1986/1987 and, because of its good eating qualities and high market value, most sport-anglers retained some of their catch. The estimated annual catch of bass taken by anglers in 1987 (Dunn et al. 1989) was 415 t, compared with landings of 630 t estimated for the commercial fishery.

Due to the socio-economic importance of both commercial and recreational fisheries, inshore fishers and sport anglers represent important stakeholders that need to be taken into account to achieve a sustainable exploitation of the stock. Moreover the deep knowledge they have on the sea bass ecology and distribution is an added value that can help scientists to gain a more comprehensive picture on the current state of the species in Welsh waters. For all these reasons we plan to strongly involve the inshore fishers and the sport anglers in generating valuable information on biological and ecological aspects of the species, as well as in providing indicators on the current state of the stock. We are also planning to provide the sector with new data collection methods (e.g. new styles of data record sheet, individual kits for biological data collection, onboard cameras, applications for I-phone, etc.) to facilitate data collection and the depth and quality of the data collected.  

In the future these new tools and detailed information will significantly contribute to improving management initiatives for a sustainable use of this resource.

Please get involved and contact:

 

The European Sea bass (Dicentrarchus labrax)

The Sea bass is a demersal fish that can grow to a length of 100cm. It has silver flanks with a pale underside and large scales. Juveniles have black spots on the upper body. It has two dorsal fins, the anterior one contains 8-9 spines and the posterior one spine and 12-13 fin rays.

Habitat & Distribution

Sea bass are found in temperate waters ranging from the Mediterranean to Norway. They are usually found in shallow coastal waters at a depth of around 10m but have occasionally been caught down to 100m depth. They are found in most habitats, including brackish estuarine waters, and can travel a considerable way up river.

Life cycle

Sea bass reach sexual maturity after approximately 5 years for males and 6 years for females. At approximate lengths of 35 cm for males and 42 cm for females, bass attain maturity and adopt the migratory movements of the adult fish. Mature adult bass migrate from summer feeding grounds in coastal waters to offshore winter spawning grounds. This occurs in October in response to the cooling of inshore waters. After spawning the larvae remain in the water column for approximately two months. They then drift inshore and recruit to estuarine nursery areas as post-larvae. Juveniles exhibit strong fidelity for nursery areas, remaining in an estuary for the first 4-5 years of life (Jennings & Pawson, 1992). They become increasingly mobile within their nursery area as they mature. At a length between 32 and 42cm, bass enter their adolescent phase. They become much wider ranging and begin to disperse. After maturation, adults exhibit more predictable migratory routes between their winter spawning grounds and their selected summer feeding grounds, showing strong site fidelity.