Breeding the Yellowline Arrow Crab (Stenorhynchus seticornis)
Stenorhynchus seticornis is a western Atlantic spider crab whose females brood fertilized eggs on their pleopods and release planktonic zoea larvae. Captive rearing is not realistically achievable.
Overview
Stenorhynchus seticornis is a long-legged spider crab of the family Inachidae from the western Atlantic, ranging from North Carolina and Bermuda through the Caribbean to Brazil on coral reefs at depths of about 3–9 m. The carapace reaches up to 6 cm with legs spanning around 10 cm. It is nocturnal, territorial and shows negative phototaxis, feeding on small feather duster worms and other reef invertebrates.
Sexing
As in other crabs, the sexes are distinguished by abdominal shape, and a gravid female is identified by the egg mass carried on her pleopods. Mating involves the male transferring a spermatophore to the female, after which she fertilizes and broods the eggs.
Conditioning
A varied carnivorous diet of small reef invertebrates maintains adults in condition, and the species is territorial, so housing more than one requires space. No documented protocol reliably induces or completes reproduction in a home reef, because the larvae are planktonic and cannot be reared in a display.
Breeding Setup
No practical home breeding setup exists. After spermatophore transfer the female carries fertilized eggs on her pleopods until they hatch into zoea larvae, which then enter the plankton and require open-water rearing conditions unavailable in a closed system.
Spawning & Larvae
Fertilized eggs are carried on the female's pleopods until ready to hatch into zoea larvae. The larvae swim toward the ocean surface and feed on plankton, developing through several molts before metamorphosing into the adult form. This extended planktonic phase is the central obstacle to captive rearing.
Common Challenges
- Surface-seeking planktonic zoea are removed by filtration and skimming.
- Larvae require continuous planktonic food over multiple molts.
- Territorial adults are aggressive toward conspecifics.
- Adults may prey on small tankmates, complicating cohabitation.