LONGLINE BY-CATCH Back to ECO

I have had it in mind to write this for some time now, what has caused me to hesitate is my empathy with and sympathy for those who are out there working the longlines. These man are one of the last remnants of this countries independent owner-operator fishing fleet which has mostly been swallowed up by the big companies under the quota management system. The tuna longline fishery is about the last way anyone can get into commercial fishing on their own behalf without having to buy hugely expensive quota. Any keen recreational fisherman will understand that fishing is either in you or not, these fellows want to be out there not behind a desk or anywhere else. It’s not an easy life on a tuna longline boat, 20 to 30 miles of line are set at night to avoid catching sea birds, after a few hours sleep while the boat and line drift, often in different directions, they steam back to the beacon on the end and start hauling. If things go well with no major tangles or cut-offs by sharks, trawlers or anything else that went past in the night, the line may be on board by early afternoon, then the fish have to be iced down and carefully stowed in the fish room. With a bit of luck someone may get a chance of more sleep while they steam to the next nights start point. Combine that with 30kt winds, the government putting levies and charges on everything they can think of and I’m sure some of them wonder why the hell they bother. I’ve got no problem with them catching as many tuna as they can. BUT what I do have a problem with is the by-catch. We are fortunate in this country that marlin may not be kept by any commercial boat, in most other parts of the world they are fair game and get killed in huge numbers, for instance studies show that surface longliners take 85% of blue marlin killed in the Atlantic and that 35% of tags returned from striped marlin tagged in New Zealand are caught by longliners. Extrapolation of that figure leaves little doubt that well over 35% of all striped marlin are killed by longliners in the Pacific. Conversely broadbill swordfish are afforded no such protection. Studies show that without curtailment of longline fishing broadbill will be commercially extinct in the Atlantic within ten years. There used to be a thriving harpoon fishery along the North American seaboard where specially built boats with a long bow pulpit were used to harpooned mature broadbill basking on the surface, this was sustainable as only mature fish were taken. Now this fishery is only a memory and longliners in the same area are lucky to get a few fish of up to 50kg. How does the New Zealand broadbill situation stack up? Surface longlining by domestic vessels is relatively new, previous to the inception of the EEZ there were a few foreign longliners which visited on a seasonal basis, they no doubt took large quantities of broadbill as it was a virtually untapped resource. Now the local boats have taken over, an ever increasing fleet is fishing, in most cases, year round. This is putting increasing pressure on what is probably a fragile resource, this is showing up in the smaller average size of broadbill being caught this year. I understand there are a large number of fish of between 10kg and 20kg being landed, with the price that is paid ( currently between $7and $8 a kg ) it’s well worth bringing home these
little fish. Although I believe some small ones are released, I suspect it’s very few. The cornerstone of MoF’s new and continuously being renewed ( shouldn’t they have got it right first time? ) legislation is sustainabil utilisation of the resource, it seems in the case of broadbill sustainability is not even being considered. To my mind a strong broadbill fishery is to everyone’s advantage and killing immature fish now is only making the same mistakes as have been made in other fisheries which are proving to be to their near fatal detriment. For any Idea of what should be done we need to take a closer look at the species. There hasn’t been much if any research done in New Zealand but as broadbill are a cosmopolitan species with almost world-wide distribution overseas studies give us a good idea of what we are looking at. Broadbill are largely solitary, live to an age of 25 years and attain a weight of over 600kg. Are found in seas with water temperatures ranging from 41 degrees F to 80 degrees F. Are considered reproductively mature by age 5 at a weight of 75kg for females and by age 3 at a weight of 35kg for males. There is a probability that there is an imbalance in the sexes as 83% of broadbill landed in the USA are immature females. While there is only one species world-wide stocks are probably area specific to the shelves of continents, or in New Zealand’s case countries, there will be some intermingling of stocks but the main concentrations of this top line predator are where the food is, in proximity to land. The key to maintaining or increasing stocks of anything whether it be saving the kakapo, sheep farming or sustaining fish stocks is allowing the species to breed, killing anything before it has a chance to reproduce is a sure path to extinction. So the solution to sustainability of New Zealand broadbill stocks is simple. Impose a minimum size limit under which no broadbill may be landed by anyone, recreational or commercial, even if an undersize fish is dead when it comes to the boat it may not be kept. Sure there would be waste as a percentage of undersize fish would have to be dumped dead but even if that was as high as 50% it still means that 50% of what is killed now would survive. Using the arbitrary size limit for marlin of 90kg would seem to be about right as this would allow females to breed at least once before they could be taken. If you want more information on broadbill have a look at these web sites :
http://www.projectsea.org/Facts/index.html http://www.seaweb.org/swordfish/ , http://members.tripod.com/~LASword/ .
Now we come to sharks, definitely not a target species of the New Zealand longline fleet but a big by-catch none the less. Pelagic sharks are deemed to be such a valuable species by MoF that they have imposed a recreational limit in the South island of one shark per person of each species per day yet it is OK for longliners to kill and discard tons every day. The only part of sharks caught on New Zealand surface longlines that are utilised are the fins which are lopped off and sold for soup. Shark fins are big business, nobody knows how many tons are sold annually world-wide each year but anyone who’s interested can have a look at :http://www.envirowatch.org/shkstory.htm where there are photos of 11 tons of fins being unloaded from a boat in Hawaii. The local fleet doesn’t land those sort of quantities but I have heard of 100kg of fins off one set, I don’t know what the fins off a mako or blue would weigh but I suspect it would need two or three average size fish to make a kilo of fins. There is at present a video circulating in the States of sharks being hauled in on a longline, having the fins and tails chopped off then kicked over the side still alive to die in their own time. It’s easy to get emotional over things like that and I’ve read some pretty gruesome commentaries on the practice, I hope it doesn’t happen here but there is a distinct possibility. Sharks are very versatile when to comes to utilisation, as well as the meat being palatable ( some species more than others ) there are markets for the skins, cartilage and even the teeth. Sharks may be a bloody nuisance to longliners not only chopping off hooks and lines but also mutilating valuable tuna. My stance is that nothing should be killed unless it is going to be used and I don’t consider the taking of fins as being a legitimise use for sharks. So again we have a simple solution; sharks must be released unless the bodies are going to be landed, to get the fins you have to bring home the trunks as well. If industry wants the fins it’s up to them to develop markets for the rest of the fish which shouldn’t be to difficult in what we are told is a protein starved world. Possibly if a specific fishery develops for sharks a size limit may have to be imposed in the future. As I said at the start I haven’t got an argument with those out there fishing, they are doing the best they can under the rules set down by the powers that be. If the Government is serious about sustainable utilisation now is the time to regulate what is a still young fishery to ensure that broadbill and pelagic sharks are not decimated by longlines as they have been overseas. As well as a commercial industry New Zealand has the opportunity to develop a multi-million dollar recreational fishery for broadbill and game sharks in a world where they are becoming increasingly rare.

Back to ECO

Captain Bert Lee E-mail: bert@charterfishing.co.nz