Species diversity to cetacean conservation and fishery management
Ni I-Hsun1*, Huang Shiang-Lin2, Chou Lien-Siang2,
Shih Nien-Tsu1 and Dai Xio-Zhen1
1
Department of Environmental Biology and Fisheries Science, National Taiwan Ocean
University. 2Institude of Ecology and Evolution Biology, National Taiwan University, Taiwan
Major contents of biodiversity are species, genetic and ecological diversities. How to link the
species diversity to conservation and management would be important concerns to all species
diversity researchers. Life history strategies can be examined from life history traits (i.e.
reproduction, growth, death, etc.) that are the underlying determinants for cetaceans and fishes
responses to phylogenetic relationship and ecological adaptation. The objective of these life
history strategy studies is using the life history traits to estimate marine animal fitness (growth
and feeding) and reproductive optimal allocation.
In cetacean case study, we are using lengths at birth, weaning, mature, and asymptotic, age at
mature, longevity as well as periods in gestation, lactation and calving interval. Cetaceans evolved
with two suborder and extant lineages arisen with 14 families and 83 species. We collect life
history traits from worldwide-published papers and books and then examined these variables
collectively with general linear model, factor analysis, and discriminant analysis among
phylogenetic taxa. We then regroup evolutionary taxa based upon statistical significance and
interpret from ecological/ethological meaning. These results would offer a feasible way to study
life history patterns and be valuable basis for wildlife conservation and management.
We then applied these pattern studies into 74 Taiwan commercial fish species with 7 life history
traits (adding growth coefficient, instantaneous natural mortality, egg diameter and fecundity),
explaining 81.9% of the total variance. Fishes can be significantly divided into two groups of
teleosts and elasmobranches. The reproductive strategies diversified significantly between teleosts
and elasmobranches due to the latter one have low fecundity with large egg diameter. In addition,
at least two statistically significant groups of teleosts and three groups for pan-perciformes were
classified based upon classes and families.
In sharks, rays and skates, they have diversified reproductive life history strategies: oviparous,
ovoviviparous, and viviparous. There were 448 Elasmobranchii species for reproduction analyses.
The new 3 factors in principal component analysis from selected 6 variables can explain 98.6% of
the total variance. Discriminate analysis was then utilized to verify reproductive modes. There
were 71 to 95% correct classification were obtained in Elasmobranchii and Rajiformes among
oviparous, ovoviviparous, and viviparous. These statistically significant reproductive life history
patterns in shark, skate and ray can serve as basis for multi-species fisheries management and also
may make up for rare and unknown species for conservation measures.
Key words: cetacean, whale, dolphin, shark, fish, ecology, life history strategy, pattern