[!tag=DT] [□]
[!tag=DT] [□=□]
[!tag=DT] [!□]
Of a total of 82 species of fish in these wetlands , 19 are commercially important for human consumption , 25 species have value as aquarium species and 16 are exploited by sport fishermen . The Savannah Sparrow has a significantly higher volume of medulla compared to the two more mesic species . You can see that they are n't commercial species , with the exception maybe of catfish . And collecting ducts than the mesic species . Research efforts currently focus on a few species : there is a need to use a broader range of model species to assist the transfer of information from research to commercial species . The wood of the true hickories is known for its strength , and no commercial species of wood is equal to it in combined strength , toughness , hardness , and stiffness ( 18 ) . Catch levels for an individual fishery are based not simply on maintaining the population of the commercial species , but on minimising the impact on dependent species as well . " , CephBase has 3,175 referenced localities for 328 species in the database . " We have shown that species with larger brains relative to their body size experience lower mortality than species with smaller brains , supporting the general importance of the cognitive buffer hypothesis in the evolution of large brains . In certain portions of its range , it can be an undesirable competitor of commercial species during early stages of stand development .