Tragic state of affairs

Steve O'Shea

TONMO Supporter
Staff member
Nov 19, 2002
Attached is an image taken from a report (details to follow, separate post). This map ONLY depicts the distribution of FISHERIES RESEARCH bottom trawl stations around New Zealand (a couple of vessels over time). I must stress that it DOES NOT DEPICT the COMMERCIAL FISHING bottom-trawl stations around New Zealand; nor does it depict where they have trawled in international waters (outside the 200 mile EEZ), as the industry is not required to report where they are (it appears that they are not accountable to anyone)!

The data is also old! The reality is worse.

The reality is that the seabed around New Zealand, to 1000 metres depth (in the majority of places), and to 1500 metres depth in a number of places, has been extensively, irreparably impacted. If commercial fishing effort (private sector) data was public domain, and the distribution of their fishing effort was superimposed on that of the fisheries research effort (government-funded fisheries research), then the entire seabed around New Zealand (and a lot of it in international waters) would be black.

The reality is that it is too late for New Zealand, for conservation of deep-sea resources/biodiversity. Moreover, the impact on the seabed and benthic communities is absolute, and is not restricted to the area immediately hit by the devastating bottom trawl. Sediment suspended in a deathly congesting plume behind the net smothers everything adjacent to the trawl corridor. In coastal waters we know that sediment deposits as inconsequential as 3mm depth have annihilated seabed communities, if the deposit (a veneer) persists for 4 or more days (we are talking total annihilation).

I will post more information soon. It is information like this that sickens me, and the reason that Greenpeace are so active in New Zealand. The fishing industry are perpetuating so many lies; they think that the public are stupid.

The problems faced in New Zealand will be being experienced everywhere, any country, where there is a continental shelf that extends offshore. Whatever you do, if you eat fish, ask how it has been caught. If the retailer cannot tell you then don't purchase it. Any fishery (finfish and shellfish) that uses bottom trawling to capture the target species IS having a significant impact on the seabed and associated communities. Don't eat bottom-trawled fish & shellfish species.

Sorry for my rant.

I hadn't considered the indirect impact bottom trawling had. Also i know that Hectors dolphin which is endemic to NZ is adversely affected by indesciminant trawlers!! :frown:

Did some quick research:

"Until recently the New Zealand government had imposed a ban on net fishing in the territory of the Hectors dolphins. However this ban was overturned at the beginning of April and since then, 3 dolphins have died in trawler nets. At this rate we will see the swift extinction of this species."

These are only the reported deaths! Most go unreported. Attached is a picture of a hector's dolphin caught by a trawler and left to die



This time we can't entirely lay the blame for Hectors dolphin deaths at the stern of the commercial trawl fishers.

By far the largest cause of deaths in Hectors dolphins (among other spp) is set netting. This is where the net is set out and left to catch whatever. As the nets are monofilament and inshore (where incidentally you find Hectors- they're not often found more than 5km offshore) the dolphins simply don't see them. Set nets can be set by commercial fishers but HEAPS are set by recreational fishers. Theoretically they're supposed to check them every day but they don't and that's too late for a dolphin anyway.

In Akaroa Harbour (near Christchurch) there is a ban on set netting over summer when the dolphins are most likely to be there. But it may be too little too late.

The subspecies Maui's Dolphin (North Island Hectors) are in worse shape.

In case you're wondering a) where I get my Info and b) what this has to do with cephs, well a) Drs Steve Dawson and Liz Slooten, NZ's foremost Hector researchers were my lecturers and I still chat with them from time to time and b) Hectors eat cephs!!!!!!!!


Just as a matter of interest, do we have any data on recovery time of the deep-sea communities? Like if they recover at all...I'm thinking research along those lines is out of the question because of the time frame involved. Say a deep-sea fish (like the Smooth Oreo Dory Pseudocyttus maculatus *plug, plug*) is fished to (near)extinction, we'd be talking a minimum of 21 years for males to reach maturity (31 for teh females according to the data i've got) if the whole community is messed up by the trawls, what would be the recovery time? Are we talking 50? 80? 150 years? How long does it take to rebuild a community, to go through the (usual) succession of pioneer species which change the substrate to allow less hardy species to colonise?

I'm of course assuming that recovery is possible at all, the deep-sea adds that extra unknown to the lot since it's so much harder to keep track of what's happening (as opposed to monitoring recovery time after an event on the shore).

Am I making sense here? or am I just rambling? Do you want fries with that?


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