Reinventing Ma/Jilgement, 1996, page 25

bubble or any empirical result will be natal streams, hatcheries, and fish farms. potentially flawed .and backed on The elements are deposited into the skeletal assumptions that might be wrong. Short teml structure of growing fish and remain management has to based on data collection throughout the life span in scales, otoliths and on short teml information. and vertebrae. Variation in chemistry of the environment produces a pattern of discrete bands in the biota corresponding to the Carl Walters changes in chemistry and the duration of A Mse stock market analyst won't ever exposure. A micro-analysis of these regions predict the market, he will develop a portfolio allows the establishment of data to provide of investments that will make the client feel specific information on the unique as safe as they want to be, Mthout having to elemental signatures (finger prints) in fish predict what will happen. from a particular source, and subsequent exposure to environmental changes during What do you see the prospects are for the migration. A classification accuracy of up to ecomodels that you have been working on for 100% is achieved when fish scales are the last few years? Will it solve the prediction examined. problem for us at all?

JamesScandal Using mass-balance ()food In-seasonestimates are easier to manage. If web models to structure dynamic something goes drastically wrong and there (ECOSIM)simulation models are no fish when we thought there were going to be a whole lot, then at least you have some fallback mechanism with in-season Carl Walters, Villy Christensena & management. Any model -even a fancy mechanistic model with some weird geometry Fisheries Centre, UBc, Vancouver,Canada or a strictly good correlation -needs to be aICLARM; Manila, Philippines ready to be knocked out of the system if it looks as if there is incompatible information coming in from the short term data Demonstration collection. The linear equations which describe I think models need to be slaughtered as trophic fluxes in mass-balance, food web soon as the need occurs. models of ecosystems (such as in the ECOPATHapproach and software) can be re- expressed as differential equations defining trophic interactions as dynamic Laser Ablation ICP-MS -A New Method relationships varying with biomasses and to Identify Individual Natal Stream regimes. The trajectories of Sources of Salmonids and Migration biomass predicted by these differential Patterns of Fish equations, and equilibrium system responses under different exploitation S. H. Wang & R. Brown. regimes are found by setting the Bemental ResearchInc., VancouveI;DC differential equations equal to zero, and solving for biomasses at different levels of Poster fishing mortality. This approach, incorp- orated as a routine (called "EcoSIM")into Laser ablation inductively coupled plasma the well-documented ECOPATHsoftware mass spectrometry (lA- ICPMS) has been (see also Pauly and Christensen, this vol., applied as a method to determine elemental page 23) will enable a wide range of distribution in biological tissue spedmens, potential users to conduct fisheries policy providing high spatial resolution and analyses that explicitly account for sensitivity. It has been determined that ecosystem trophic interactions, without certain elements are assimilated into growing req~ the users to engage in detailed biota from the food source and fresh water in information gathering (beyond that Reinventing Fisheries Managemnt, Workshop Report, page 28

those looking at oceans were looking more at can we say about what has transpired? ~ ecosystem-based management. Marine protected areas might be perhaps a tool for A person of my school of thought looks at that latter form of management. this sort of ecosystem stUff and says it doesn't really help because it is so I am on a fisheries resource conservation unpredictable and so it doesn't help solve coWlcil on the Atlantic coast of Canada that the problem. On the other hand, the other tIies to deal \\lith recommending conservation school looks at me and says, well you idiot, measures to the government. We have been of course these fish eat this and eat that suuggling \\lith issue like this and we face and how can you possibly ignore these facts questions like does it make sense to harvest about the process. capelin when the cod stodks are depressed. and does it make sense to trawl on the It seems to me a theme of this meeting is bottom of the ocean when that disturbs the try to see each other as Sherlock Holmes. bottom habitat? How do we bridge between the two schools? Your question Tony was in some sense Those kind of issues are ones raised by the unanswerable. You would have to be an fishers that we listen to. To me those are the idiot to disagree that the food web matters fundamental questions that are out there, somehow. But is the ecosystemperspective and I would be interested in any comments as germane to the analysis? This is important to how to address them, apart from saying we because of the ~se of ecosystem need more research. research. Where do we focus our attention for data? What is useful for the taxpayer? TonyPitcher I wonder how many of us feel about I might say Jim that I thought that your talk incorporating the ecosystem perspective in a was one of the most convindng that I have managementplan. How many people here feel ever heard on how things can really happen. that we have enough knowledge and the right I guess it was expensive and you had the tools to confidently include the ecosystem privilege of being able to manipulate things aspectin conventional ? a bit. The question I have for you is that I am talking about more than just the single some of the manipulations in your system species management. -the fish population were handed to you, either by nature or by dynamics that traditionally have been used by virtue of the fact that publicity brought in fisheries managers. Do we know enough the sports fishermen. Other times you went after sessions like today, to include that in and moved fish. It seems to me that most our management? of us have to depend a lot on naturally induced contrasts. JakeRice There is not a yes or no answer. In some jake Rice areas we have some knowledge that we could On that theme, and prompted by Tony's use to do ecosystem based management. For question, studies of marine ecosystems, example. we have excellent experience with whether they are pelagic, open ocean or tuna-dolphins and with other spedes of whatever, have taught us a great deal over bycatch, I wouldn't go further on other the last three decades. examples. That is the approach that we are trying to pursue but I wouldn't be bigheaded But if you look at the assessment tools enough to assumewe can do it. being used for fish stocks, and try to build analytical linkages between the research on john Schnute ecosystems and actually doing the stock It does seem as if there are two schools of assessment to provide forecasts in the thought. I belong to a school where a great short and medium term -I raise my hand to deal of my professional energy is directed Tony Pitcher's question and say yes- we do towards looking at the data we actually have know a lot, we know a great deal, but we are and trying to decide what is actually not using these analytical paths to give happening out there. This is very Sherlock advice to managers. And I don't know a Holmes-like -here are the fmgerprints and jurisdiction in the world that is providing the footprints and all the clues, and now what fWlding to build those links. We are

~1 it Reinventing Fisheries Manilgement, 1996, page 29

funding lots of ecosystembased research and suggest that this claim not really true, but lots of modelling on fish stocks, but we are the discussion is symptomatic of our not linking those two things. It seems very reluctance to get involved. Ullglamorous work but it is where we are going to get the payoff. The freshwater people know more about their systems because they more bounded RashidSumaila or coupled than marine ones, and so maybe We have several systems, from the fjords to they are more confident to use knowledge the Barents Sea to the North Sea, where we of the ecosystem in resource management. can see that the production of phytoplankton But our profession is very unhappy at the can be modelled from the local conditions, notion of trying to use such knowledge in but the biomass of zooplankton cannot be the oceans. modelled from the local phytoplankton concentrations, only from the advection from There is an instructive paradox here: the the open ocean. public may be surprised at our professional coyness. We say that we do not have the For instance, the Norwegian Sea supplies the knowledge to manage aquatic resources whole Barents Sea (which is three times the using information about their roles in size of the North Sea). It is driven by ecosystems. Yet as several speakers have advection. Fish production is not driven by pointed out, we humans have already local conditions but by input from the documented massive impacts on marine Atlantic. This is not similar to a lake. systems. $0 we may have the basis for more understanding more than we care to admit. Kevem Cochrane Can I respond to that, and put folWard a gross oversimplification, but then that is Several speakers pointed to massive what modelling is an about! I suggest that we uncertainties and unpredictability in could take one of Jim's half hectare models aquatic systems. But similar massive and with minima] change apply it to the Black uncertainties are incorporated as a matter Sea,but in doing so we would have to split it of routine into everydaystock assessments. up into 4-5 little areas,and we would have to We baulk at the uncertainties of including model interactions between those areas. We prey, predator and trophic web effects, but could apply it to the Mediterranean. but we often these trophic interactions turn out to would have to split it up into 20 -30 different be supported by food consumption data areas, and look at ticIeinteractions between dating back many years. I suggest that we areas.And we could go on to do the same for try to have the courage to develop and use the Pacific Ocean. with many little coupled ecosystem-based managementtools. areas.

What would be happening is that the interaction terms would be becoming more and more dominant. So what was happening in the box (for example what Jim was telling us) would become less and less important, and what is happening between the boxes would become more and more important. This leads to the uncertainty that we talked about earlier.

TonyPitcher The naturalistic fallacy in philosophy is to try to get an is from an ought. As scientists we are adept at avoiding this pitfall -we know we ought to use ecosystemmanagement, but this discussion shows that we are very eager not to use it becausewe like to claim we dont know what it is. The papers in this session