BASS met with Defra in June 2011. Data produced by Cefas on bass catches/landings in England and Wales and provided by Defra during and after that meeting is now available.
Download the original document: Cefas bass discards data v2 (Age compositions and discarding of bass in the uk commercial fisheries)
Download the BASS response: BASS response to Cefas
You can also read the full BASS response to Cefas below…
Response to Cefas data (v2) provided during and after a meeting with Defra and Cefas in June 2011
Summary
The information provided by Cefas is deeply worrying and further confirms the view of BASS and many bass anglers that UK bass stocks are a shadow of where they were before commercial exploitation took off, with much fewer larger adult bass than is healthy.
The most shocking graphs show that most bass landed by trawlers (and to a lesser extent gill netters) are between 4 and 7 years old with very few fish landed over 8 years old. This is shocking because bass (females) do not breed successfully until they are 6 to 7 years old. Trawlers (predominantly otter trawling) are taking out future breeding stocks before they have chance to breed and replenish stocks. As these are landings, we can assume that fish below the current Minimum Landing Size (MLS) were also caught and then discarded (dead).
We see the same evidence from the graphs showing catches (as opposed to landings) by otter trawlers with the (most common) smaller net sizes analysed by length (in cm). The key length is 48cm (being the minimum breeding size of 42cm+, plus the annual growth of 6cm). Again we see virtually no fish caught above 48cm and we see the fish below 36cm (the current MLS), being discarded.
IT IS CLEAR THAT THE LOW MINIMUM LANDING SIZE OF 36CM IS ENCOURAGING, INCENTIVISING AND REWARDING TRAWLERS TO CATCH BASS BEFORE THEY HAVE A CHANCE TO BREED AND REPLENISH DEPLETED STOCKS. WHAT IS EQUALLY WORRYING IS THE ABSENCE OF LARGER ADULT BASS IN TRAWLER LANDINGS. IT IS LIKELY THE REASON FOR THIS IS A COMBINATION OF THE LACK OF ADULT BASS AROUND OUR SHORES AND THE FINANCIAL INCENTIVE DUE TO THE LOW MLS FOR TRAWLERS TO TRAWL NEAR NURSERY AREAS WHERE JUVENILE BASS CAN BE CUAGHT BEFORE THEY DISPERSE INTO THE ADULT POPULATION. THIS WILL ALSO RESULT IN CATCHES OF BASS BELOW THE MLS WHICH ARE THEN DISCARDED (AS WE SEE IN THE CATCHES CHARTS).
The information provided also shows gillnetting (the largest commercial catching method) similarly catching most fish before they reach breeding size (because the low MLS encourages and rewards them for doing this). Commercial Rod and Line catching of bass is the second most valuable commercial fishing method in the UK (third by weight) but is barely covered by the information supplied.
The size and age distribution of bass caught by rod and line looks different to catches by trawlers (in particular) and gillnetters as larger bass can be targeted by fishing method and location and for this reason, data from rod and line fishing is not representative of overall bass stocks and should not be used, on it’s own, for bass stock assessments. What is noticeable and shocking is that even this method is showing a sparcity of bass that have been breeding for several years, especially as bass can live to 20+ years (if not caught).
NO ALLOWANCE IS MADE ANYWHERE IN THE DATA FOR INCREASING FISHING EFFORT OR THE EFFECTIVENESS OF THAT EFFORT, FOR THIS NON QUOTA, HIGH COMMERCIAL VALUE, SPECIES.
Details
The report should be read in conjunction with the following facts about bass:-
- They are slow growing and late maturing, with females only able to breed successfully at 42+cm in length (6 to 7 years old) and bass can live to 20+years of age.
- The current Minimum Landing Size is 36cm.
- Commercial landings of bass have never exceeded £5m p.a. (MMO statistics) compared to an estimated value of recreational sea angling for bass of £100m+ p.a.
- To ensure all bass have had at least one chance to spawn and replenish stocks a prudent Minimum Landing Size should be 48cm (42cm minimum breeding size plus one years growth of 6cm to allow for catches at any time of year)
- Bass can live to over 20 years of age
See Figure 1.2 of the Cefas bass discards data v2 (Page 4)
This shows that the very strong 1989 year class were all fished out by 2003. Initial breeding of this year class would have lead to the small upswing in 10+ year old fish in 2006/2007, but the small size of this upswing possibly indicates how many of these fish were caught before they could breed and even this small upswing only lasted 2 years. This remarkable year class would have had an abnormally positive impact on the graphs in Fig 1.1 ( see page 3 of the CEFAS discards data v2)
See Figure 1.3 of the Cefas bass discards data v2 (Page 5)
This shows firstly the weakness and inaccuracy of ICES stock assessment models, which do not bear a good correlation to actual breeding results, as shown on the bottom graph (from the now discontinued Cefas young bass sampling surveys). Secondly it shows how the 1989 year has not been repeated since, with only the 1997 year coming close. Evidence discussed above of the fate of the 1989 year class suggests that the 1997 year class has probably now also been fished out.
See Page 6 Discussion of the Cefas bass discards data v2
Increasing the MLS to 48cm, as discussed above, would remove the incentive for trawlers to continue to make the trawls shown particularly in Figure 2.4 (see page 11 of CEFAS bass discards data) with the small mesh size, as there would be very few takeable bass to catch. Hence increasing the MLS to 48cm would REDUCE DISCARDS as well as allowing bass to reach breeding size. If these trawlers still want to trawl near to nursery areas to target skates and rays a much larger mesh size may allow catching of these species whilst allowing undersized bass to escape (as would square mesh panels).
See Figure 2.2 of the Cefas bass discards data v2 (Page 9)
Note beam trawling only accounts for 1 – 2% of commercial bass landings. The comparative lack of larger adult bass is shocking.
See Figure 2.3 of the Cefas bass discards data v2 (Page 10)
This area includes the Thames, with it’s nursery areas. Again, there is a shocking lack of larger adult bass as well as high discards of baby bass (below 36cm) suggesting possible targeting of fish near the actual protected nursery areas.
See Figure 2.4 of the Cefas bass discards data v2 (Page 11)
The most shocking graphs of all. Clear targeting of immature bass and a very serious lack of adult bass from the second most important (by weight) commercial catching method. An MLS of 48cm would render these trawls for bass pointless as there would be barely any fish of a takeable size to pay for the costs of the trawl, thus reducing discards by reducing discards from these existing trawls.
See Figure 2.5 of the Cefas bass discards data v2 (Page 12)
These graphs suggest increasing mesh size on an otter trawl (existing mesh pattern), even to 100mm to 119mm still results in catches of immature bass.
See Figure 2.6 of the Cefas bass discards data v2 (Page 13)
These graphs show the strong size selectivity of gill nets. With gillnets being comparatively cheap, gillnetters could adapt to a higher MLS easily.