Research published in the Royal Society’s Biology Letters journal suggests that fisheries management must consider population demography.

Modeling the life history demographics of 25 different marine fish species, Canadian scientists have found that larger, older female fish produce tougher offspring than their younger counterparts.

In efforts to make fisheries more sustainable, conserving the elder female fish could help sustain populations. Currently the findings of the research are out of sync with real-life fisheries practice, where the largest fish are sought. Overfishing results from this practice because of the two-fold effect of removing the best breeders, and subsequently reducing the rate of recruitment in the local population.

It is suggested that by enforcing size regulations, altering the size of fishing gear and how it’s used could protect the bigger older individuals. The practicality of implementing these measures on the ground are not explored explicitly however, and targeting large female fish within populations could be very difficult to implement.

Do blog readers believe that European fisheries practices are sustainable? Does the Common Fisheries Policy need re-evaluating?

Blog readers are invited to comment on this article

It seems as though the Government-Industrial complex has overcome sensibilities in a move by the International Commission for the Conservation of Atlantic Tunas (ICCAT), calling to maintain fishing levels of bluefin tuna Thunnus thynnus 50% above scientists’ recommendations.

ICCAT members decided to permit a take of 22,000 tonnes per year (Total Allowable Catch), despite ICCAT scientists setting a quota of 15,000 tonnes (TAC). The members voted on the higher quota despite warnings by scientists that fisheries would collapse if their advice was not heeded. The ICCAT members’ target does not even take into consideration the additional 30% of take that illegal fishing contributes.

Some European countries have independently expressed concern over bluefin stocks. Spain, which consume the most tuna of any European country, called for a suspension of the fishery, whilst Italy have opted for a total moratorium.

It is thought that conservation groups may now engage the Convention of International Trade of Endangered Species (CITES), in order to enforce trade control over the bluefin tuna trade.

Europeans, particularly the British, have a tendency to favour very few fish species over the relative diversity of fish available on the market. There are many decent alternatives to popular choices such as Atlantic cod and bigeye tuna (stocks of both are perilously depleted), its simply a matter of educating the public, and where possible your colleagues.

The Marine Conservation Society has provided a comprehensive sustainable fish guide, and a pocket-sized version is available from their fish online website.

The IUCN have today announced the findings of an investigation into the state of the North Atlantic’s rays and sharks; 26 per cent of these face extinction with 20% ‘near threatened.’

The estimated percentage is conservative however, insofar as many of the species (27%) assessed lacked sufficient data to effectively assess their status. Even the conservative estimate of 26 per cent threatened, is much greater than the global average of 18 per cent.

The primary cause of their alarming status is overfishing. As the annual meeting for EU quotas looms closer, there will be opportunities to bolster the recovery of these species.

Sonja Fordham, Deputy Chair of the IUCN SSG and Policy Director for the Shark Alliance called for government officials to listen up and take notice:

“Country officials should heed the dire warnings of this report and act to protect threatened sharks and rays at national, regional and international levels. Such action is immediately possible and absolutely necessary to change the current course toward extinction of these remarkable ocean animals,”

This report highlights the urgent need to ratify the Marine Bill, due to be announced in the forthcoming Queen’s speech.

Marine Biologists have disturbingly discovered that some of the UK’s harbour seal Phoca vitulina vitulina populations have and are undergoing ‘massive’ declines. The results are particularly concerning given that scientists are as yet, unable to account for exactly why these declines are occurring at their present rate.

Ian Boyd, a professor with the sea mammals research unit at St Andrew’s University said:

“This is very abnormal. To give you an idea of the level of abnormality, the rates of decline are equivalent to these populations producing no offspring for five or six years.”

The declines coincide with reports that other groups in these areas (Orkney islands and East England) such as sea birds are undergoing similarly rapid declines. Last month scientists at the University of Stockholm reported that their ‘junk food hypothesis‘ could offer some explanation to the declines. The theory goes, that as key prey populations in the North Sea such as cod Gadus morhua have depleted to near extinction, fish such as sprat Sprattus sprattus have grown considerably in abundance, replacing the cod’s ecological niche. However despite their abundance, they lack the nutritional value of cod leading to leaner seabirds and lower survival rates in young.

Other theories researchers have put forward include an increasing range overlap with gray seals Halichoerus grypus resulting in greater competition, direct persecution at fishing grounds by shooting, and a greater reported abundance of killer whales around Orkney and the North sea, leading to increased mortality of seal pups.

The report comes at a time when Scotland is consulting on a Scottish Marine Bill. Conservationists have called for the abolishment of the Seal Conservation Act that permits seal shooting near fisheries, and for protection under the existing Wildlife & Countryside Act.

Since top predators such as seals are sensitive to perturbations in community dynamics, the declining trend seen in many of their British populations should be a considerable cause for concern. Continued monitoring will provide a better understanding of whether this is a natural fluctuation in their population dynamics or a more concerning trend.

Blog readers are invited to comment on this article

A report released by the Joint Committee on the Marine Bill says that the funding is inadequate and the provisional powers allocated of the representative bodies of the Marine Bill are insufficient.

Lord Greenway, of the Joint Committee, says that the bill must “commit the secretary of state to take action” rather than just “enable change” to take place.

The report recognises recommendations made by the British Ecological Society (BES) and its members, in recommending that the creation of marine reserves be ‘underpinned by [sound] science.’ And Natasha Barker, senior marine policy officer at the WWF echoed the BES response saying that the MMO must have majority responsibility in planning offshore renewable and energy projects. The report also expresses concern over how the Government plans to enlist the support of the devolved administrations – essential for making the bill work.

Whilst the draft Marine Bill may have shortcomings and areas for improvement, it is an incredibly important and essential piece of legislation for the whole of the UK. Therefore it is essential that the government takes on board the recommendations from the report and of the relevant stakeholders, ensuring that the key marine conservation measures are implemented – a central aim of the Marine Bill.

The Joint Committee’s findings can be read here:

http://www.publications.parliament.uk/pa/jt200708/jtselect/jtmarine/159/159i.pdf

New research published recently in Estuaries and Coastal Science indicates that current policy and knowledge of invasive species in coastal and estuarine areas is seriously lacking.

Shipping may introduce invasive non-native species (INNS) through the emptying of ballast water in estuarine areas, or through species attached to the hull, often these may have originated thousands of miles from where they are released. Fish farming and aquariums are also significant potential INNS sources.

The authors of the paper call for further research by scientists and greater attention from policy-makers and stakeholders. The researchers suggest that prevention and early detection are the most effective methods of dealing with INNS. Further, screening using historically invasive-traits and matching previous habitats with potential new habitats, could help predict the likelihood of future invasions into alien environments.

This is of particular relevance given that the draft Marine Bill presently does not provide any reference to the introduction of INNS into the marine environment, nor any legislative preventative measures. The CBD and the Codes of Practice on the Introductions and transfers of Marine Organisms set by the International Council for Exploration of the Seas are not binding and carry no fixed penalties, therefore unless the Marine Bill addresses these issues in its final iteration, a great opportunity will have been missed.

Do readers of the blog agree that the Marine Bill should address the introduction of invasive non-native species into the marine environment?


Read the BES’s Parliamentary Office of Science & Technology (POST) fellow’s POSTnote.

Further information on the British Ecological Society’s POST fellowship can be found on the website.