A new study finds that drastic cuts in fishing quotas have not helped cod recover because rising temperatures have also decreased reproduction and increased mortality.
A team of marine scientists found that rising temperatures in the gulf decreased reproduction and increased mortality among the once-plentiful Atlantic cod, adding to the toll of many decades of overfishing.
A recent hypothesis is that the population of hares rises and falls due to a mixture of population pressure and predation: when hares overpopulate their environment, the population becomes stressed — the fact that the food supply is gobbled up certainly doesn't help — which can lead to decreased reproduction, resulting in a drop in next year's hare count.
A recent hypothesis is that the population of hares rises and falls due to a mixture of population pressure and predation: when hares overpopulate their environment, the population becomes stressed the fact that the food supply is gobbled up certainly doesn't help which can lead to decreased reproduction, resulting in a drop in next year's hare count.
Eventually, the benefit of producing stronger defenses and tolerances will be outweighed by the detriment of decreased reproduction.
This often leads to susceptibility to diseases, reduced growth and decreased reproduction thus diminishing productivity (Pickering 1993; Schreck 1996: Schreck et al. 2001).
The results indicated that exposure to AgNPs led to increased ROS formation, increased expression of PMK-1 p38 mitogen-activated protein kinase (MAPK) and GST enzyme activity and decreased reproduction, which suggested the role of oxidative stress as a significant mechanism of AgNPs-induced reproduction toxicity.
An interaction study with P. arrhenomanes and the migratory ectoparasitic nematode Tylenchorhynchus annulatus showed a significantly decreased reproduction rate of the nematode when co-inoculated with a high oomycete inoculum (Bond et al. 2004), revealing that this antagonism is not only limited to sedentary nematodes.
In contrast, cadmium (Cd), chromium (Cr), zinc (Zn), lead (Pb), and copper (Cu) decreased reproduction of Steinernema feltiae, S. carpocapsae, and H. bacteriophora and lowered their virulence against the wax moth, G. mellonella (Jaworska and Gorczyca, 2002 and 2009 and Sun et al., 2016).
A potential mechanism for decreased reproduction is the effect of stress in response to human presence [26] [28].
