|
Ocean
|
" Gray Seal was bitten by a shark and made its way out to shore in an attempt to survive. As it eventually bled out, birds most likely enjoyed a quick snack of eyeballs "
Jorge Severa Hauser: " Mother and calf in the shallows. Somewhere in Baja. "
@PaulNicklen | The largest walrus I have ever seen rests on a bed of ice in Svalbard, Norway. His tusks had to be at least three feet long. He was immense in girth and stature, nearly as tall as he was wide. Standing in the presence of a mammal as powerful and large as this, you become aware of how small you are in comparison. Walrus have not been hunted in Svalbard for over 60 years, leaving these leviathans to exist in peace for decades. I hope that their peace is protected.
Follow me @PaulNicklen for more stories from the Arctic, and to learn why it is one of my favorite places in the world. 
Seasonal variation in Arctic marine mammal acoustic detection in the northern Bering Sea
Abstract Declines in Arctic sea ice cover are influencing the distribution of protected endemic marine mammals, many of which are important for local Indigenous Peoples, and increasing the presence of potentially disruptive industrial activities. Due to increasing conservation concerns, we conducted the first year‐round acoustic monitoring of waters off Gambell and Savoonga (St. Lawrence Island, Alaska), and in the Bering Strait to quantify vocalizing presence of bowhead whales, belugas, walruses, bearded seals, and ribbon seals. Bottom‐mounted archival acoustic recorders collected data for up to 10 months per deployment between 2012 and 2016. Spectrograms were analyzed for species‐typical vocalizations, and daily detection rates and presence/absence were calculated. Generalized additive models were used to model call presence as a function of time‐of‐year, sea surface temperature, and sea ice concentration. We identified seasonality in call presence for all species, corroborating previous acoustic and distribution studies, and identified finer‐scale spatiotemporal distribution via occurrence of call presence between different monitoring sites. Time‐of‐year was the strongest significant effect on call presence for all species. These data provide important information on Arctic endemic species' spatiotemporal distributions in biologically and culturally important areas within a rapidly changing Arctic region. 
On World Wildlife day yesterday, I learnt some fascinating facts about something a few pisces like Viper Dogfish & Goblin Sharks can do. Many fishes can extend their both jaws forward or laterally to suck in food particles, but these can all but detach there apart from the skull.
Viper Dogfish (East China sea, Philippines sea, Yellow sea)  *This image is copyright of its original author Goblin Shark (almost all tropical & temperate coastal waters)  *This image is copyright of its original author
Global Documentary
A 392-year-old Greenland shark recently discovered in the Arctic Ocean. Which means this shark was alive in 1627! Greenland sharks have a life of about 400 years. Most are blind because of an eye parasitic. Their meat is toxic and they don't attack humans.  *This image is copyright of its original author
Alex Mustard: " Silky silhouette. Diving in Cuba is very much about the big animals and sharks are abundant on all the sites in Jardines de la Reina - which is something that divers just aren’t used too. Almost everywhere we go they are fished out. I’ve a load of shark pictures to share as I churn through my recent images, but thought I’d start with this eye catching silky silhouette that shows off the elegant lines of this pelagic shark (and I could process it in seconds - taking much longer to write this caption)! "
(03-26-2020, 01:12 AM)Pckts Wrote: Global Documentary Longest living members of Animalia. Oldest one is estimated to be more than 500 years old.
Jorge Cervera Hauser: " Member of the Mobulidae family and the largest of all rays, the pacific giant manta can reach a wingspan of 15ft (4.5m). "
An illuminating idea to reduce bycatch in the Peruvian small-scale gillnet fishery
Abstract Found in the coastal waters of all continents, gillnets are the largest component of small-scale fisheries for many countries. Numerous studies show that these fisheries often have high bycatch rates of threatened marine species such as sea turtles, small cetaceans and seabirds, resulting in possible population declines of these non-target groups. However, few solutions to reduce gillnet bycatch have been developed. Recent bycatch reduction technologies (BRTs) use sensory cues to alert non-target species to the presence of fishing gear. In this study we deployed light emitting diodes (LEDs) - a visual cue - on the floatlines of paired gillnets (control vs illuminated net) during 864 fishing sets on small-scale vessels departing from three Peruvian ports between 2015 and 2018. Bycatch probability per set for sea turtles, cetaceans and seabirds as well as catch per unit effort (CPUE) of target species were analysed for illuminated and control nets using a generalised linear mixed-effects model (GLMM). For illuminated nets, bycatch probability per set was reduced by up to 74.4 % for sea turtles and 70.8 % for small cetaceans in comparison to non-illuminated, control nets. For seabirds, nominal BPUEs decreased by 84.0 % in the presence of LEDs. Target species CPUE was not negatively affected by the presence of LEDs. This study highlights the efficacy of net illumination as a multi-taxa BRT for small-scale gillnet fisheries in Peru. These results are promising given the global ubiquity of small-scale net fisheries, the relatively low cost of LEDs and the current lack of alternate solutions to bycatch.
Functional diversity of marine megafauna in the Anthropocene
Abstract Marine megafauna, the largest animals in the oceans, serve key roles in ecosystem functioning. Yet, one-third of these animals are at risk of extinction. To better understand the potential consequences of megafaunal loss, here we quantify their current functional diversity, predict future changes under different extinction scenarios, and introduce a new metric [functionally unique, specialized and endangered (FUSE)] that identifies threatened species of particular importance for functional diversity. Simulated extinction scenarios forecast marked declines in functional richness if current trajectories are maintained during the next century (11% globally; up to 24% regionally), with more marked reductions (48% globally; up to 70% at the poles) beyond random expectations if all threatened species eventually go extinct. Among the megafaunal groups, sharks will incur a disproportionate loss of functional richness. We identify top FUSE species and suggest a renewed focus on these species to preserve the ecosystem functions provided by marine megafauna
Timing is everything: Survival of Atlantic salmon Salmo salar postsmolts during events of high salmon lice densities
Abstract
Jorge Cervera Hauser: " A compilation of images shot with a smartphone. While having pro equipment will get you the highest quality images resolution-wise, and a wide range of optics, it should never be a limitation. In my personal experience, not having my pro gear with me has pushed me to try and get more creative and make nice photos by adapting my vision to the tool that I have at hand.
1. Octopus / Lanai / Galaxy S8 (no housing) 2. Gray Whale / Magbay / iPhone 11 Pro Max 3. Great White / Guadalupe / iPhone X (Kraken Housing) 4. Orcas / Sea of Cortez / iPhone 11 Pro Max 5. Great White / Guadalupe / iPhone X (Kraken Housing) "
" What's that below!
A Whaleshark approaches from the depths of the Ningaloo Reef. " |
| Users browsing this thread: |
| 1 Guest(s) |