Team 2 mindmap by Quek Zhi Jian

Spine Tail Devil Ray

quekzhijianrx7 — 2024-11-15 04:47:09 UTC

Introduction

2024-11-15 04:52:14 UTC

genetic variation (Cherfrlyn and Josh)

2024-11-15 04:53:56 UTC

Heterozygosity (Josh)

2024-11-15 04:55:25 UTC

Heterozygosity is the expected probability that an individual will be heterozygous at a given locus.

For the spine tail devil ray it showed that the Ho was 0.310 and the Hs was 0.257, the inbreeding coefficient for the ray is -0.209. Since the inbreeding coefficient is negative it shows that there is more outbreeding than inbreeding.

What is affecting them (ZJ)

2024-11-15 04:55:54 UTC

Overexploitation (90,000 are caught annually for their gill plates [For Chinese medicine], 61,000 kg annually and estimated to be worth USD11.3 million
Slow Growth Rate (producing only one pup on average every 1–3 years, and likely has a very low intrinsic rate of population increase.
Pollution (Microplastics, Heavy metals and toxins accumulate in their bodies, impacting reproduction and lifespan)

conservation actions

2024-11-15 04:56:56 UTC

Mobulids were listed on appendix I and II of CMS in 2014, protecting the species and work regionally towards conservation

Species is covered by CMS memorandum of understanding for Migratory Sharks and a special suite of 'Concerted Actions', which are aimed at facilitating conservation.
In 2012, the General Fisheries Commission for the Mediterranean (GFCM) banned retention and mandated careful release for these species
In 2015, IATTC prohibited Mobula species caught by large-scale fisheries in the IATTC Convention Area from being retained, sold, etc., and mandated prompt, careful release

fun facts

2024-11-15 04:58:40 UTC

According to fossil records it’s believed that devil rays have been around for around 20-25 million years.
Giant devil rays are commonly found in the Mediterranean and eastern Atlantic, whilst pygmy devil rays prefer the Indian Ocean and Western Pacific.
Devil rays are closely related to stingrays, although only the spinetail mobula (mobula japonica) has a stinger at the end of its tail.
while feeding, devil rays can dive to depths of nearly 2km for around 60-90 minutes, at speeds of 13mph (22km/h), making them the fastest and deepest divers in the ocean.

description

2024-11-15 05:06:31 UTC

Phylum: Chordata

Family :Mobulidae

class: Chondrichthyes

Spine Tail Devil Ray (Mobula mobular) are circumtropical marine animals (distributed in tropical region) often extending their range into warm temperate latitudes.

Random genetic drift (Cherfrlyn)

2024-11-15 05:37:33 UTC

Population size:

Spine tail devil rays are migratory and typically have larger populations, but if specific groups become isolated due to habitat loss or other factors, genetic drift could reduce genetic diversity.

Founder effect:

If small groups of spine-tail devil rays are displaced of migrate to new areas, they may experience a founder effect, where the genetic variation of the new group is limited compared to the original population.
This could result in less genetic diversity, further affecting their adaptability

Habitats

2024-11-15 05:54:43 UTC

Marine netric(pelagic)- less than 50m of water but can dive at depth of 1112m

Marine Oceanic - Epipelagic (0-200m), Mesopelagic (200-1000m) and Bathypelagic (1000-4000m)

Diet

2024-11-15 05:56:53 UTC

Filter feeders

Main food: small fish, zooplankton, crustaceans, and ichthyoplankton

Genetic variation (Josh)

2024-11-15 05:57:24 UTC

From the two locations that the live at (Dawei and Myeik). These two areas are separated by 200 km. There was only a 1.2% genetic difference between the two clusters. Even though they have live 200km away from each other and it is not a far distance for the highly mobile devil rays. The genetic difference between the clusters could be explained by the different feeding grounds and low migration rates.

Importance of genetic variation (Cherfrlyn)

2024-11-15 05:59:55 UTC

Allow species to adapt to environmental changes, survive, and reproduce
Allows natural selection to increase or decrease the frequency of alleles in a population
Help species avoid inbreeding, which could reduce their ability to survive and reproduce
Gives species the ability to evolve and respond to environmental changes

Conservation status and threats

2024-11-15 06:04:44 UTC

IUCN red list: Endangered

Threats: Fishing & harvesting aquatic resources

description:These rays are captured in a wide range of gear types including harpoons, drift nets, purse seine nets, gillnets, traps, trawls, and longlines. Their coastal and offshore distribution, and tendency to aggregate makes mobulids particularly susceptible to bycatch in purse seine and longline fisheries, targeted capture in artisanal fisheries, and incidental entanglement

Effective population size (Josh)

2024-11-15 06:07:41 UTC

The devil ray has low effective population size. As in the study the breeding sex ratio of the devil ray is 24 females to 6 males . Which means that there are fewer effective breeding pairs which can reduce genetic diversity,

Overfishing

2024-11-15 06:26:11 UTC

It is the main cause of the genetic diversity decreasing. Overfishing not only results in population decline but also loss of genetic diversity and evolutionary potential. Genetic variation can increase extinction risk and reduce recovery rats of the endangered species.