Coastal sea spider

Systematic position. Pycnogonum littorale belongs to the class Pycnogonida, order Pantopoda, and family Pycnogonidae. These unique marine arthropods are morphologically adapted to benthic life, characterized by a robust body and specialized appendages used for both locomotion and reproduction.

Biology and life cycle. The species is primarily found in littoral and sublittoral zones. Its life cycle involves an egg-carrying phase performed by the males, followed by a parasitic larval stage. Juveniles often seek host organisms, such as sea anemones, to attach to and derive nutrition, completing their development before reaching the adult stage.

Nature of damage. In the context of aquaculture and marine biology, this species acts as an ectoparasite. By attaching to soft-bodied marine organisms via a suctorial proboscis, they drain body fluids, causing physical trauma and physiological stress to the host, which can lead to significant biomass loss if the host is a commercially valued species.

Impact on marine ecosystems. Their presence can disrupt the balance of integrated multi-trophic aquaculture (IMTA) systems. Since they naturally inhabit intertidal zones, they can infiltrate water intake systems of marine farms, potentially establishing localized populations that continuously prey on sensitive marine species or fouling organisms used in filtration.

Control measures. Mitigation strategies for aquaculturists involve strict mechanical filtration of water intake systems. The use of fine-mesh screens and UV-C sterilization helps prevent the colonization of rearing tanks by these sea spiders. Regular monitoring of water intake pipes is recommended to remove egg masses and adult specimens before they can cause economic harm.