Division of Customs Biosecurity Deputy Director James Deleon Guerrero and customs inspectors hold the vials containing the black widow spider and little fire ants during a press conference at the Customs office on Thursday.
Photo by Emmanuel T. Erediano
THE Division of Customs Biosecurity is stepping up efforts to prevent invasive species from entering the CNMI, Customs Director Jose Mafnas and Deputy Director James Deleon Guerrero told reporters on Thursday.
During a press briefing at the Customs office at the Port of Saipan, Mafnas and Deleon Guerrero emphasized the importance of intercepting invasive species — especially those not yet present on the islands — at ports of entry.
Over the past two months, Customs inspectors have intercepted two invasive species aboard vessels docked at the Port of Saipan: two black widow spiders on Sept. 17, 2025, and a colony of little fire ants on Aug. 14, 2025. The black widow spiders were found beneath a container, while the little fire ants were discovered in the bottom of palletized cargo containing heavy metals.
“It is something we are very concerned about, so we are taking a serious approach to ensure the CNMI remains free of invasive species,” Mafnas said, noting that inspectors rigorously check all incoming shipments at every port of entry.
While facilitating shipments is beneficial to the economy, Mafnas said Customs will not compromise the integrity of its biosecurity efforts. Importers could face significant costs if invasive species are found in their shipments, including mitigation and treatment fees.
Deleon Guerrero said the federal government is increasing its focus on invasive species. CNMI Customs officials have participated in multiple regional forums highlighting the importance of protecting U.S. territories from harmful species.
Guam, he noted, currently hosts over 60 types of invasive species. “Because Guam is so close to the CNMI and there is frequent travel both ways, this is something we are very concerned about here,” he said.
Depending on the type, invasive species can severely impact plants and the environment. For example, the cicada moth — a butterfly-like insect — could potentially kill pine trees that help control beach erosion. Little fire ants can harm native birds and even pose risks to infants and toddlers due to their swarming attacks.
“We don’t want these species entering the CNMI. Not only are they dangerous to our children, but they can also kill native bird species. That is how dangerous little fire ants are,” Deleon Guerrero said.
Regarding black widow spiders, Mafnas said this species is not present on any CNMI island and cannot be allowed to establish a population.
Deleon Guerrero added that rhino beetles are causing damage on Rota, consuming palm trees — including coconuts — which are an important food source for the island’s coconut crabs.
“If we don’t control these species at our ports of entry and they make it into the community, it could cost millions of dollars to mitigate. Just containing them in a secured area would cost hundreds of thousands of dollars. That’s really important for the public to understand,” Deleon Guerrero said.
