Pelagic shrimp play dead in deep oxygen minima.

Benjamin P Burford,Kim R Reisenbichler,Kyra L Schlining,Bruce H Robison

doi:10.1371/journal.pone.0207249

Benjamin P Burford, Kim R Reisenbichler + Show 2 more

Open Access

https://doi.org/10.1371/journal.pone.0207249

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Abstract

Pelagic crustaceans are arguably the most abundant group of metazoans on Earth, yet little is known about their natural behavior. The deep pelagic shrimp Hymenopenaeus doris is a common decapod that thrives in low oxygen layers of the eastern Pacific Ocean. When first observed in situ using a remotely operated vehicle, most specimens of H. doris appeared dead due to inactivity and inverted orientation. Closer inspection revealed that these animals were utilizing small, subtle shifts in appendage position to control their orientation and sink rate. In this mode, they resembled molted shrimp exoskeletons. We hypothesize that these shrimp may avoid capture by visually-cued predators with this characteristic behavior. The low metabolic rates of H. doris (0.55–0.81 mg O2 kg-1 min-1) are similar to other deep-living shrimp, and also align with their high hypoxia tolerance and reduced activity. We observed similar behavior in another deep pelagic decapod, Petalidium suspiriosum, which transiently inhabited Monterey Canyon, California, during a period of anomalously warm ocean conditions.

Highlights

The pelagic environment is the largest inhabitable space on the planet, and in many regions contains deep hypoxic layers occupied by animals that are adapted to low oxygen conditions [1]
We documented the behavior of H. doris in situ during a warm climate period in the Gulf of California [28] using a remotely operated vehicle (ROV), and investigated its metabolism through shipboard respirometry measurements on captured specimens
Hymenopenaeus doris predominantly spent the daytime hours in deep oxygen minimum zones (OMZs), with a few found in deeper, oxygen limited zones (OLZs) (Fig 1)

Summary

Introduction

The pelagic environment is the largest inhabitable space on the planet, and in many regions contains deep hypoxic layers occupied by animals that are adapted to low oxygen conditions [1]. We documented the behavior of H. doris in situ during a warm climate period in the Gulf of California [28] using a remotely operated vehicle (ROV), and investigated its metabolism through shipboard respirometry measurements on captured specimens.

Results

Conclusion