MILBEMYCIN OXIME (INTERCEPTOR) TREATMENT OF PYCNOGONID SEA SPIDER INFESTATION IN THREE SPECIES OF CORALS.

Area of Science:

• Marine Biology
• Aquatic Toxicology
• Coral Reef Ecology

Background:

• Coral reef systems can experience pest outbreaks, such as pycnogonid sea spiders.
• Sea spider infestations negatively impact coral health and survival.
• Effective and safe treatments are needed to manage sea spider populations in aquaria.

Purpose of the Study:

• To evaluate the efficacy of milbemycin oxime immersion therapy for controlling pycnogonid sea spider populations in coral.
• To determine the optimal dosage and treatment frequency of milbemycin oxime for sea spider eradication.
• To assess the safety and impact of milbemycin oxime treatment on coral health.

Main Methods:

• Sixteen coral colonies of three species (Stylophora pistillata, Pocillopora damicornis, Acropora tenuis) were subjected to milbemycin oxime immersion therapy.
• Initial trials used a dose of 0.016 ppm, followed by a doubled dose of 0.032 ppm in subsequent treatments.
• Treatments were administered weekly, with histopathology and biopsies used to monitor coral health and treatment effects.

Main Results:

• The initial dose of 0.016 ppm milbemycin oxime was ineffective in reducing sea spider numbers.
• A higher dose of 0.032 ppm, administered weekly for three treatments, significantly reduced the pycnogonid sea spider population.
• Histopathological analysis and post-treatment biopsies confirmed no adverse effects on the health of the three coral species.

Conclusions:

• Repeated weekly immersion treatments with 0.032 ppm milbemycin oxime are effective for reducing pycnogonid sea spider populations.
• This therapeutic approach is safe for Stylophora pistillata, Pocillopora damicornis, and Acropora tenuis corals.
• Milbemycin oxime offers a viable solution for managing sea spider infestations in reef aquaria.