Анализ степени альтернативности динамики обилия разных видов при отсутствии непрерывных рядов длительных наблюдений на примере нектона Охотского моря

• Main Author: Волвенко, И.
• Format: Text
• Language: unknown
• Published: Федеральное государственное унитарное предприятие «Тихоокеанский научно-исследовательский рыбохозяйственный центр» 2004
• Subjects: Atka; Okhotsk; Sockeye; okhotsk sea
• Online Access: http://cyberleninka.ru/article/n/analiz-stepeni-alternativnosti-dinamiki-obiliya-raznyh-vidov-pri-otsutstvii-nepreryvnyh-ryadov-dlitelnyh-nablyudeniy-na-primere-nektona; http://cyberleninka.ru/article_covers/14528252.png

На примере нектона Охотского моря рассматривается простой количественный метод классификации видов на альтернативные (с противофазной динамикой обилия), комплементарные (колебания обилия которых совпадают по фазе) и независимые (их флюктуации не согласованы между собой). Получена корреляционная матрица, характеризующая структуру населения пелагиали и позволяющая предсказывать изменения состава и соотношения видов, что может быть полезно для долговременного планирования структуры промысла при многовидовом рыболовстве. Показано, что в современную эпоху при продолжающемся увеличении биомассы кеты можно ожидать дальнейшего возрастания в нектоне доли горбуши, нерки, симы, кижуча, одноперых терпугов и камчатского кальмара. Одновременно будет снижаться доля миктофид, хаулиода, пепельного макруруса, охотского липолага, серебрянки, малоглазого макруруса, сельди, лемонемы и минтая. Наступление же очередной сардиновой эпохи приведет к увеличению в нектоне доли стихеевых, а также уменьшению доли анчоуса, песчанки и терпугов, круглоперовых, скорпенообразных, минтая, охотского липолага, двулопастного бычка и сельдевой акулы. Long-term (with periods of several years or decades) fluctuations in abundance are usual for some fish species. They are generated primarily by variability in climate and oceanographic environments. Certain species have different requirements for habitat conditions, therefore their abundance may oscillate differently. Alternative species (as well as complementary and independent ones) could be easy revealed in fish community with the help of standard statistical methods of time series analysis. Unfortunately, the long-term observations are frequently incomplete, or reflect rather fishery dynamics than the real state of species abundance. In turn, the commercial fishery depends both upon fish stocks and accessibility of fishery areas and species, fishery market, etc. A new simple quantitative method allows to reveal the alternative species in the case when there are no continuous long-term data collected simultaneously for many species. The Okhotsk Sea square was split into 257 one-degree trapeziums. The average density (in kg/km2) was calculated for total nekton (M) and for 47 taxonomic groups of nekton (m1, m2, , m47) in each trapezium for 3 periods: 1980-s, early 1990-s, and 19962003. Then the share of weight Pi = 100 mi/M (in %) was calculated for each group. The resultant DP = (Pi2 Pi1) + (Pi3 Pi2) = Pi3 Pi1 (lies between 100 % and +100 %) reflects the changes of a group (i) within a trapezium between the periods. It can be either positive, representing increase, or negative, representing decrease of a certain nektonic group, with zero meaning no change. In the orthogonal system of coordinates, where DP for one species is plotted on the abscissa and DP for an other species is plotted on the ordinate, every point indicates the degree of alternation for abundance dynamics of those species within a trapezium. The point in the 1st (upper right) or 3rd (lower left) quarters on the plot corresponds to simultaneous increase or decrease in abundance of both species. The point in the 2nd (upper left) or 4th (lower right) quarters on the plot corresponds to the case of alternative species, when an increase in abundance of one species is accompanied by the decrease in abundance of the other. In case the point lies on an axis, one of the species either retains its abundance or is totally absent in the region. A total of 257 points on the plot describe general average trend within the whole sea area. Multispecies relationships can be described by a correlation matrix. As the matrix was obtained not from the actual biomass estimations but from the shares for each species or group, it is independent from any changes in total nekton biomass. In other words, the matrix reflexes a structure of pelagic community. This feature of the matrix could be used for practical purposes, e.g. for long-term planning of multispecies fishery structure. For the Okhotsk Sea, the resultant matrix shows that during the recent period of enhanced chum abundance we must also expect further rise in abundance of pink, sockeye, masu, coho, atka mackerels, and shortarm gonate squids. At the same time, the share of lanternfishes, viperfishes, popeye grenadier, popeyed blacksmelt, smoothtongue, giant grenadier, herring, hakeling, and pollock will decrease. The next "sardine" period will result in higher share of snake-bennies, and lower share of anchovy, sand lance and atka mackerels, lumpfishes, scorpion fishes and rock-fishes, pollock, popeyed blacksmelt, crested sculpin and salmon shark.