The Changing Tides: Climate Change Impacts on Marine Animal Reproduction in South Africa
Climate change is defined as the long-term changes in global or regional weather patterns as well as average temperatures caused by human activities.
It has significant implications for marine animals, particularly those that rely on temperature changes for breeding and other vital life processes. The picturesque coastal cities of Durban and Cape Town in South Africa are not only popular tourist destinations but also home to diverse marine ecosystems. Rising temperatures change ocean currents and weather patterns that impact marine habitats. The article will explore challenges faced by South Africa’s marine animals due to rising temperatures, focusing on their reproduction and the conservation efforts required to protect these animals.
This reliance on temperature, known as thermal dependence, can be seen in various marine vertebrate organisms, such as fish, turtles, seals, seabirds, and invertebrates like corals and molluscs. According to IUCN Red List, Green Sea turtles (Chelonia mydas) are endangered and loggerhead sea turtles (Caretta caretta) are vulnerable, these are two species affected by temperature-dependent sex determination (TSD), meaning that the temperature during the incubation period determines the gender of the hatchlings. Cooler temperatures result in more males, while warmer temperatures lead to more females.
It is concerning that the rising temperatures due to climate change create unfavourable conditions for survival and lead to skewed sex ratios which may negatively impact the populations. For example, if predominantly females are produced, it can disrupt the breeding dynamics and can potentially reduce reproductive success.
Many fish species including coral reef fish such as bicolor wrasse (Halichoeres bicolor) and squaretail coral grouper (Plectropomus areolatus) are known to have TSD. In these species, more males are produced in cooler temperatures, and females are produced in warmer temperatures. The impact of rising temperatures on fish species can disrupt the gender imbalance, affecting breeding success and population stability.
Rising temperatures cause coastal breeding habits such as coral reefs and mangroves to be threatened or degraded due to sea-level rise, ocean acidification, and altered ocean currents, making it challenging for species that rely on these habitats for breeding and early life stages.
Seabirds are also affected in terms of breeding timing, distribution, and abundance of prey species that sea birds rely on is being altered or reduced which impacts survival and reproduction rate. In times of extreme weather events, including storms and heatwaves, the nests are destroyed leading to egg or chick mortality and even adult mortality if feeding opportunities are compromised.
Protecting the beaches and implementing conservation measures such as shading nests or relocating eggs to cooler areas, can help mitigate the impacts of rising temperatures on sea turtle population. Also, by monitoring of the temperatures in the nests aiming to maintain a balanced sex ratio and ensuring long term survival. In fish species, protecting critical habitats such as coral reefs and mangroves, implementing responsible fishing practices and monitoring, can mitigate impact of temperature on reproduction.
As South Africans, it is important to take care of our marine ecosystems by minimizing the negative impacts of contaminants, cleaning beaches, and keeping them clean from visible dirt. Through Community engagement, education, awareness and proper waste management, it can be achieved.
It is very important to promote the importance of marine animals and foster responsible behaviour through educating people about marine species, and their habitats such as mangroves, involving local communities, fishermen, and policymakers. Proper waste management including establishing innovative waste management systems and through campaigns to clean the beaches.
In brief, addressing climate requires a collection of action, cooperation, and commitment from governments, communities, and individuals, including high school and university students. Changes in temperatures unfavourable conditions for marine species and the environment. By involving strategies which will mitigate climate change and involve everyone’s voice and action. We can protect marine ecosystems which plays an important role in economic circulation.
