TITOV O.V., SHAMRAY E.A.
Polar Research Institute of Marine Fisheries and Oceanography (PINRO), Russia

Development and exploitation of oil and gas resources on the shelf undoubtedly affect the environment and biota.

In most cases modern technique provides for preventing or minimizing consequences of anthropogenic influence on particular land or sea areas and/or living organisms.

The compensation for the immediate damage caused by the area pollution or loss of bioresources can be both a financial and restoring one (e.g. water body purification or reproduction of bioresources). However, these actions produce positive results only in the event of instant influence and damage detection. As a rule, some consideration is only given to pollution exceeding certain standards and causing loss of valuable bioresources, whereas any changes in habitat conditions or cumulative effects are not evaluated.

The juvenile release shall contribute to the restoration of valuable biological resources after a time. The recovery of food base for a resource, be it plankton of trash fish, and changes in habitat conditions (availability of spawning areas, chemical composition of water) have not been even examined. As a flexible system the nature is adaptable and self-restoring and a “volley” discharge does not necessarily lead to substantial changes in habitat conditions. However, the consequences of immediate or cumulative pollution can be evident in the distant future. To predict and work out in time a plan of actions to prevent and minimize such consequences is only possible on the basis of permanent monitoring and prediction of a situation from different perspectives.

The necessity of environment monitoring and short-time forecasting “where the oil spills will move” as well as the need for measures to remove consequences are clear to everyone. However, the question arises as to how one can interpret a situation where the pollution is lacking but the fishing, e.g. fishing for cod, is impossible due to fish absence. Is this a usual occurrence depended on normal environmental conditions or a result of cumulative anthropogenic impact that produced condition changes? The answer can be probably given on the basis of many-sided comparison of the current situation with the retrospective one.

In our view, the analog method is a tool which, though providing no precise and complete answer, allows at least to identify the reasons behind the situation under consideration.

The analog method is well known. It has been applied in many areas and has a number of advantages and disadvantages. All processes are characterized by continuity and repeatability. Each specific process can be considered as a result of interrelated and compelled processes. The forecast precision depends on a number of available retrospective data and forecast periods. It is reasonable that short-time forecasts show the most precision. The main disadvantages of this method are a probability of a situation that an analog is indeterminable or a situation that the environment characteristics have undergone a change in recent years and/or such changes take place at the present time. For example, if the data observed wholly correspond to such data collected 100 years ago but the abundance of feeding zooplankton in a specified area differs from the today’s one this suggests a different development of the situation. On the other hand, revealing such an “anomaly” can point to fundamental changes in the environment. In future an effort should be made to reveal the reasons for the said “anomaly”, remove its consequences and take adequate corrective actions.

Nonlinear systems provide several solutions under the same initial conditions. With the same analog much different scenarios may be realized. This depends upon the fact that selected analogs are not necessarily true analogs or that the changes occurred and their dynamics have not been considered. The permanent monitoring system allows updating the selected analogs in advance and enhancing the forecast reliability. The same is true for revealing (determining) “anomalies” in the current situation and reason behind them.

The forecasting system applied in PINRO is a technological process incorporating collection and processing of oceanographic, fisheries and biological information, its evaluation, preparation of the forecast itself, appraisal by experts, approval and introduction of the forecast.

The information base for forecasting is as follows:

data from long-term oceanographic and meteorological investigations;
data from long-term biological investigations of aquatic bioresources;
dynamics of synoptic, oceanographic and biological processes in different time scales;
retrospective and present stock status of aquatic bioresources including non-exploited resources;
peculiarities of forming of bioresource aggregations and dynamics of their spatial-temporal distribution in relation to environmental conditions and biological cycles;
structure and spatial-temporal stability, behavour and migration directions of aquatic bioresources;
data on predator-prey interactions;
data from long-term investigations of biology, development peculiarities, abundance dynamics and concentration formation of phyto- and zooplankton.

Permanent monitoring of the above processes makes it possible to promptly reveal any changes in the environment and/or life activity of aquatic organisms.

PINRO has been developing several forecasts for various time periods. Forecasts prepared some time ago (e.g. one year ago) has been updated on the basis of new findings.

When preparing a forecast, seasonal variability of meteorological and oceanographic conditions were estimated and years with similar characteristics were selected to determine the analogs. The forecast of water thermal state was developed and the thermal year type was identified. Data on stock state and structure are sufficiently formalized. Expected changes in size and structure of particular species stocks are forecasted on the basis of data on fisheries, loss of biorecourses for various reasons, recruitment and etc. with consideration for oceanographic conditions. The analog years in relation to oceanographic conditions and in relation to status of a specific stock do not necessarily coincide with each other. The analogs are selected for specific areas and seasons with regard to features of biological resources. When preparing forecasts the peculiarities of succession forms and analogs of previous years, homologs and their groups must be kept in mind.

In our opinion, the analog method can be applied to assess the impact of outwardly non-catastrophic, local, “regular” events of chronic pollution on the environment and biota while in production and transportation of hydrocarbon raw materials.

OIL AND GAS OF ARCTIC SHELF 2008